diff --git a/test/inspector/debugger/wasm-gc-anyref.js b/test/inspector/debugger/wasm-gc-anyref.js
index db06d325a0..5ef0dc7a46 100644
--- a/test/inspector/debugger/wasm-gc-anyref.js
+++ b/test/inspector/debugger/wasm-gc-anyref.js
@@ -66,6 +66,7 @@ async function printPauseLocationsAndContinue(msg) {
 
 async function instantiateWasm() {
   var builder = new WasmModuleBuilder();
+  builder.startRecGroup();
   let struct_type = builder.addStruct([makeField(kWasmI32, false)]);
   let array_type = builder.addArray(kWasmI32);
   let imported_ref_table =
@@ -128,7 +129,7 @@ async function instantiateWasm() {
       .addLocals(kWasmAnyRef, 1, ['anyref_local_null'])
       .addBody(body)
       .exportFunc();
-
+  builder.endRecGroup();
   var module_bytes = builder.toArray();
   breakpointLocation = main.body_offset + body.length - 1;
 
diff --git a/test/mjsunit/regress/wasm/regress-12874.js b/test/mjsunit/regress/wasm/regress-12874.js
index 58a9146ebb..b670322348 100644
--- a/test/mjsunit/regress/wasm/regress-12874.js
+++ b/test/mjsunit/regress/wasm/regress-12874.js
@@ -9,10 +9,12 @@ d8.file.execute("test/mjsunit/wasm/wasm-module-builder.js");
 
 var builder = new WasmModuleBuilder();
 
-var sig_index = builder.addType({params: [kWasmStructRef], results: [kWasmI32]});
-
+builder.startRecGroup();
+var sig_index = builder.addType({params: [kWasmStructRef],
+                                 results: [kWasmI32]});
 var sub1 = builder.addStruct([makeField(kWasmI32, true)]);
 var sub2 = builder.addStruct([makeField(kWasmI32, false)]);
+builder.endRecGroup();
 
 builder.addFunction('producer', makeSig([], [kWasmStructRef]))
   .addBody([
diff --git a/test/mjsunit/regress/wasm/regress-12945.js b/test/mjsunit/regress/wasm/regress-12945.js
index a681465db3..3dc72fa13f 100644
--- a/test/mjsunit/regress/wasm/regress-12945.js
+++ b/test/mjsunit/regress/wasm/regress-12945.js
@@ -8,9 +8,11 @@ d8.file.execute("test/mjsunit/wasm/wasm-module-builder.js");
 
 let builder = new WasmModuleBuilder();
 let i32_field = makeField(kWasmI32, true);
+builder.startRecGroup();
 let supertype = builder.addStruct([i32_field]);
 let sub1 = builder.addStruct([i32_field, i32_field], supertype);
 let sub2 = builder.addStruct([i32_field, makeField(kWasmF64, true)], supertype);
+builder.endRecGroup();
 let sig = makeSig([wasmRefNullType(supertype)], [kWasmI32]);
 
 let callee = builder.addFunction("callee", sig).addBody([
diff --git a/test/mjsunit/wasm/call_indirect.js b/test/mjsunit/wasm/call_indirect.js
index b3621687b4..6f482a4ab1 100644
--- a/test/mjsunit/wasm/call_indirect.js
+++ b/test/mjsunit/wasm/call_indirect.js
@@ -48,8 +48,6 @@ d8.file.execute('test/mjsunit/wasm/wasm-module-builder.js');
   let exporting_instance = (function() {
     const builder = new WasmModuleBuilder();
 
-    builder.setSingletonRecGroups();
-
     let struct_mistyped = builder.addStruct([]);
 
     let struct = builder.addStruct([makeField(kWasmI32, true)]);
@@ -72,8 +70,6 @@ d8.file.execute('test/mjsunit/wasm/wasm-module-builder.js');
 
   const builder = new WasmModuleBuilder();
 
-  builder.setSingletonRecGroups();
-
   // Have these in the reverse order than before.
   let struct = builder.addStruct([makeField(kWasmI32, true)]);
   let struct_mistyped = builder.addStruct([]);
diff --git a/test/mjsunit/wasm/gc-casts-from-any.js b/test/mjsunit/wasm/gc-casts-from-any.js
index 845d335b0c..4dd8e9a937 100644
--- a/test/mjsunit/wasm/gc-casts-from-any.js
+++ b/test/mjsunit/wasm/gc-casts-from-any.js
@@ -8,9 +8,11 @@ d8.file.execute('test/mjsunit/wasm/wasm-module-builder.js');
 
 (function TestRefTest() {
   var builder = new WasmModuleBuilder();
+  builder.startRecGroup();
   let structSuper = builder.addStruct([makeField(kWasmI32, true)]);
   let structSub = builder.addStruct([makeField(kWasmI32, true)], structSuper);
   let array = builder.addArray(kWasmI32);
+  builder.endRecGroup();
 
   let fct =
   builder.addFunction('createStructSuper',
diff --git a/test/mjsunit/wasm/gc-casts-subtypes.js b/test/mjsunit/wasm/gc-casts-subtypes.js
index 7208c94bf0..9225a70a2f 100644
--- a/test/mjsunit/wasm/gc-casts-subtypes.js
+++ b/test/mjsunit/wasm/gc-casts-subtypes.js
@@ -11,9 +11,15 @@ d8.file.execute('test/mjsunit/wasm/wasm-module-builder.js');
 (function RefCastFromNull() {
   print(arguments.callee.name);
   let builder = new WasmModuleBuilder();
+  builder.startRecGroup();
   let structSuper = builder.addStruct([makeField(kWasmI32, true)]);
+  builder.endRecGroup();
+  builder.startRecGroup();
   let structSub = builder.addStruct([makeField(kWasmI32, true)], structSuper);
+  builder.endRecGroup();
+  builder.startRecGroup();
   let array = builder.addArray(kWasmI32);
+  builder.endRecGroup();
 
   // Note: Casting between unrelated types is allowed as long as the types
   // belong to the same type hierarchy (func / any / extern). In these cases the
diff --git a/test/mjsunit/wasm/gc-js-interop-helpers.js b/test/mjsunit/wasm/gc-js-interop-helpers.js
index 2047862d16..3c39fc13bc 100644
--- a/test/mjsunit/wasm/gc-js-interop-helpers.js
+++ b/test/mjsunit/wasm/gc-js-interop-helpers.js
@@ -8,7 +8,6 @@ d8.file.execute('test/mjsunit/wasm/wasm-module-builder.js');
 
 function CreateWasmObjects() {
   let builder = new WasmModuleBuilder();
-  builder.setSingletonRecGroups();
   let struct_type = builder.addStruct([makeField(kWasmI32, true)]);
   let array_type = builder.addArray(kWasmI32, true);
   builder.addFunction('MakeStruct', makeSig([], [kWasmExternRef]))
diff --git a/test/mjsunit/wasm/gc-js-interop-import.mjs b/test/mjsunit/wasm/gc-js-interop-import.mjs
index 41ee0e12f7..b6266ad4e8 100644
--- a/test/mjsunit/wasm/gc-js-interop-import.mjs
+++ b/test/mjsunit/wasm/gc-js-interop-import.mjs
@@ -8,7 +8,6 @@ import {struct, array} from 'gc-js-interop-export.mjs';
 
 // Read struct and array with new wasm module.
 let builder = new WasmModuleBuilder();
-builder.setSingletonRecGroups();
 let struct_type = builder.addStruct([makeField(kWasmI32, true)]);
 let array_type = builder.addArray(kWasmI32, true);
 builder.addFunction('readStruct', makeSig([kWasmExternRef], [kWasmI32]))
diff --git a/test/mjsunit/wasm/reference-globals-import.js b/test/mjsunit/wasm/reference-globals-import.js
index 456bc92af0..4aa1697fff 100644
--- a/test/mjsunit/wasm/reference-globals-import.js
+++ b/test/mjsunit/wasm/reference-globals-import.js
@@ -13,7 +13,6 @@ d8.file.execute("test/mjsunit/wasm/wasm-module-builder.js");
 
   let exporting_instance = (function() {
     let builder = new WasmModuleBuilder();
-    builder.setSingletonRecGroups();
     let type_super = builder.addStruct([makeField(kWasmI32, false)]);
     let type_sub =
         builder.addStruct([makeField(kWasmI32, false)], type_super);
@@ -64,7 +63,6 @@ d8.file.execute("test/mjsunit/wasm/wasm-module-builder.js");
   for (let[expected_valid, type, global] of tests) {
     print(`test ${type} imports ${global}`);
     let builder = new WasmModuleBuilder();
-    builder.setSingletonRecGroups();
     let type_super = builder.addStruct([makeField(kWasmI32, false)]);
     let type_sub =
       builder.addStruct([makeField(kWasmI32, false)], type_super);
@@ -105,7 +103,6 @@ d8.file.execute("test/mjsunit/wasm/wasm-module-builder.js");
 
   let exporting_instance = (function() {
     let builder = new WasmModuleBuilder();
-    builder.setSingletonRecGroups();
     let type_super = builder.addStruct([makeField(kWasmI32, false)]);
     let type_sub =
         builder.addStruct([makeField(kWasmI32, false)], type_super);
@@ -156,7 +153,6 @@ d8.file.execute("test/mjsunit/wasm/wasm-module-builder.js");
   for (let[expected_valid, type, imported_value] of tests) {
     print(`test ${type} imports ${imported_value}`);
     let builder = new WasmModuleBuilder();
-    builder.setSingletonRecGroups();
     let type_super = builder.addStruct([makeField(kWasmI32, false)]);
     let type_sub =
       builder.addStruct([makeField(kWasmI32, false)], type_super);
@@ -214,7 +210,6 @@ d8.file.execute("test/mjsunit/wasm/wasm-module-builder.js");
   print(arguments.callee.name);
   let exporting_instance = (function() {
     let builder = new WasmModuleBuilder();
-    builder.setSingletonRecGroups();
     let type_struct = builder.addStruct([makeField(kWasmI32, false)]);
     let type_array = builder.addArray(kWasmI32);
 
diff --git a/test/mjsunit/wasm/reference-globals.js b/test/mjsunit/wasm/reference-globals.js
index 821c2b1b27..88bd2bf3b3 100644
--- a/test/mjsunit/wasm/reference-globals.js
+++ b/test/mjsunit/wasm/reference-globals.js
@@ -12,8 +12,12 @@ d8.file.execute("test/mjsunit/wasm/wasm-module-builder.js");
   var exporting_instance = (function() {
     var builder = new WasmModuleBuilder();
 
+    builder.startRecGroup();
     var sig_index = builder.addType(kSig_i_ii);
+    builder.endRecGroup();
+    builder.startRecGroup();
     var wrong_sig_index = builder.addType(kSig_i_i);
+    builder.endRecGroup();
 
     var addition_index = builder.addFunction("addition", sig_index)
       .addBody([kExprLocalGet, 0, kExprLocalGet, 1, kExprI32Add])
@@ -110,7 +114,9 @@ d8.file.execute("test/mjsunit/wasm/wasm-module-builder.js");
   print(arguments.callee.name);
 
   var builder = new WasmModuleBuilder();
+  builder.startRecGroup();
   var struct_index = builder.addStruct([{type: kWasmI32, mutability: true}]);
+  builder.endRecGroup();
   var composite_struct_index = builder.addStruct(
       [{type: kWasmI32, mutability: true},
        {type: wasmRefNullType(struct_index), mutability: true},
diff --git a/test/mjsunit/wasm/reference-tables.js b/test/mjsunit/wasm/reference-tables.js
index c54fef5218..ed556ae5fa 100644
--- a/test/mjsunit/wasm/reference-tables.js
+++ b/test/mjsunit/wasm/reference-tables.js
@@ -425,8 +425,6 @@ d8.file.execute('test/mjsunit/wasm/wasm-module-builder.js');
 
   // Equivalent struct type.
   let builder = new WasmModuleBuilder();
-  // Force type canonicalization for struct_type
-  builder.setSingletonRecGroups();
   let struct_type = builder.addStruct([makeField(kWasmI32, false)]);
   let struct_type_invalid = builder.addStruct([makeField(kWasmI64, false)]);
   let struct_type_sub = builder.addStruct(
@@ -473,7 +471,6 @@ d8.file.execute('test/mjsunit/wasm/wasm-module-builder.js');
   print(arguments.callee.name);
   let exporting_instance = (() => {
     let builder = new WasmModuleBuilder();
-    builder.setSingletonRecGroups();
     let struct_type_base = builder.addStruct([makeField(kWasmI32, false)]);
     let struct_type =
         builder.addStruct([makeField(kWasmI32, false)], struct_type_base);
@@ -482,7 +479,6 @@ d8.file.execute('test/mjsunit/wasm/wasm-module-builder.js');
   })();
 
   let builder = new WasmModuleBuilder();
-  builder.setSingletonRecGroups();
   let struct_type_base = builder.addStruct([makeField(kWasmI32, false)]);
   let struct_type =
       builder.addStruct([makeField(kWasmI32, false)], struct_type_base);
diff --git a/test/mjsunit/wasm/runtime-type-canonicalization.js b/test/mjsunit/wasm/runtime-type-canonicalization.js
index 72bcae09af..832e5c017f 100644
--- a/test/mjsunit/wasm/runtime-type-canonicalization.js
+++ b/test/mjsunit/wasm/runtime-type-canonicalization.js
@@ -7,7 +7,6 @@
 d8.file.execute("test/mjsunit/wasm/wasm-module-builder.js");
 
 let builder = new WasmModuleBuilder();
-builder.setSingletonRecGroups();
 
 let struct_index = builder.addStruct([makeField(kWasmI32, true)]);
 let identical_struct_index = builder.addStruct([makeField(kWasmI32, true)]);
diff --git a/test/mjsunit/wasm/type-based-optimizations.js b/test/mjsunit/wasm/type-based-optimizations.js
index 5ac4debefb..f6bd1ac783 100644
--- a/test/mjsunit/wasm/type-based-optimizations.js
+++ b/test/mjsunit/wasm/type-based-optimizations.js
@@ -10,6 +10,7 @@ d8.file.execute("test/mjsunit/wasm/wasm-module-builder.js");
 // (by inspecting the resulting graph).
 (function WasmTypedOptimizationsTest() {
   let builder = new WasmModuleBuilder();
+  builder.startRecGroup();
   let top = builder.addStruct([makeField(kWasmI32, true)]);
   let middle = builder.addStruct([makeField(kWasmI32, true),
                                   makeField(kWasmI64, false)],
@@ -22,6 +23,7 @@ d8.file.execute("test/mjsunit/wasm/wasm-module-builder.js");
                                    makeField(kWasmI64, false),
                                    makeField(kWasmI64, false)],
                                   middle);
+  builder.endRecGroup();
 
   builder.addFunction("main", makeSig(
         [wasmRefType(bottom1), wasmRefType(bottom2)], [kWasmI32]))
diff --git a/test/mjsunit/wasm/wasm-module-builder.js b/test/mjsunit/wasm/wasm-module-builder.js
index cf0299f9f3..f9ae8db8b8 100644
--- a/test/mjsunit/wasm/wasm-module-builder.js
+++ b/test/mjsunit/wasm/wasm-module-builder.js
@@ -1272,15 +1272,11 @@ class WasmModuleBuilder {
     this.element_segments = [];
     this.data_segments = [];
     this.explicit = [];
+    this.rec_groups = [];
     this.num_imported_funcs = 0;
     this.num_imported_globals = 0;
     this.num_imported_tables = 0;
     this.num_imported_tags = 0;
-    // If a wasm-gc type is detected, all types are put by default into a single
-    // recursive group. This field overrides this behavior and puts each type in
-    // a separate rec. group instead.
-    // TODO(7748): Support more flexible rec. groups.
-    this.singleton_rec_groups = false;
     return this;
   }
 
@@ -1339,8 +1335,6 @@ class WasmModuleBuilder {
     this.explicit.push(this.createCustomSection(name, bytes));
   }
 
-  // TODO(7748): Support recursive groups.
-
   addType(type, supertype_idx = kNoSuperType) {
     var pl = type.params.length;   // should have params
     var rl = type.results.length;  // should have results
@@ -1607,8 +1601,19 @@ class WasmModuleBuilder {
     return this;
   }
 
-  setSingletonRecGroups() {
-    this.singleton_rec_groups = true;
+  startRecGroup() {
+    this.rec_groups.push({start: this.types.length, size: 0});
+  }
+
+  endRecGroup() {
+    if (this.rec_groups.length == 0) {
+      throw new Error("Did not start a recursive group before ending one")
+    }
+    let last_element = this.rec_groups[this.rec_groups.length - 1]
+    if (last_element.size != 0) {
+      throw new Error("Did not start a recursive group before ending one")
+    }
+    last_element.size = this.types.length - last_element.start;
   }
 
   setName(name) {
@@ -1627,17 +1632,23 @@ class WasmModuleBuilder {
     if (wasm.types.length > 0) {
       if (debug) print('emitting types @ ' + binary.length);
       binary.emit_section(kTypeSectionCode, section => {
-        // If any type is a wasm-gc type, wrap everything in a recursive group.
-        // TODO(7748): Support more flexible rec. groups.
-        if (!this.singleton_rec_groups &&
-            wasm.types.findIndex(type => type instanceof WasmStruct ||
-                                         type instanceof WasmArray) >= 0) {
-          section.emit_u32v(1);
-          section.emit_u8(kWasmRecursiveTypeGroupForm);
+        let length_with_groups = wasm.types.length;
+        for (let group of wasm.rec_groups) {
+          length_with_groups -= group.size - 1;
         }
-        section.emit_u32v(wasm.types.length);
+        section.emit_u32v(length_with_groups);
 
-        for (let type of wasm.types) {
+        let rec_group_index = 0;
+
+        for (let i = 0; i < wasm.types.length; i++) {
+          if (rec_group_index < wasm.rec_groups.length &&
+              wasm.rec_groups[rec_group_index].start == i) {
+            section.emit_u8(kWasmRecursiveTypeGroupForm);
+            section.emit_u32v(wasm.rec_groups[rec_group_index].size);
+            rec_group_index++;
+          }
+
+          let type = wasm.types[i];
           if (type.supertype != kNoSuperType) {
             section.emit_u8(kWasmSubtypeForm);
             section.emit_u8(1);  // supertype count