diff --git a/src/environments/groupthm.pysty3 b/src/environments/groupthm.pysty3
index e88290d..13fef23 100644
--- a/src/environments/groupthm.pysty3
+++ b/src/environments/groupthm.pysty3
@@ -274,3 +274,15 @@ __HEADER__(Grouping theorems for easier customization.)
 [
   thmtools = { numbered = no }
 ] { starred }
+
+\DeclareTheoremGroupRule { big     } { incompatible-error } { small  }
+
+\DeclareTheoremGroupRule { all     } { lower              } { big    }
+\DeclareTheoremGroupRule { all     } { lower              } { small  }
+\DeclareTheoremGroupRule { all     } { lower              } { dagger }
+\DeclareTheoremGroupRule { all     } { lower              } { star   }
+
+\DeclareTheoremGroupRule { starred } { higher             } { big    }
+\DeclareTheoremGroupRule { starred } { higher             } { small  }
+\DeclareTheoremGroupRule { starred } { higher             } { dagger }
+\DeclareTheoremGroupRule { starred } { higher             } { star   }