diff --git a/src/environments/groupthm.pysty3 b/src/environments/groupthm.pysty3
index 7f86396..c47dee9 100644
--- a/src/environments/groupthm.pysty3
+++ b/src/environments/groupthm.pysty3
@@ -348,6 +348,23 @@ __HEADER__(Grouping theorems for easier customization.)
   }
 }
 
+\cs_new:Npn \new_theorem_variant_parser:nnn #1 #2 #3
+{
+  \NewDocumentEnvironment{#1}{#2}
+  {
+    \clist_clear:N \l_groupthm_groups_clist
+    #3
+    \__sort_group_names:
+    \begin{__#1__groups_\clist_use:Nn \l_groupthm_groups_clist{_}}
+  }
+  {
+    \clist_clear:N \l_groupthm_groups_clist
+    #3
+    \__sort_group_names:
+    \end{__#1__groups_\clist_use:Nn \l_groupthm_groups_clist{_}}
+  }
+}
+
 % envname, name, thmtools
 \cs_new:Npn \declare_theorem_variants:nnn #1 #2 #3 
 {