diff --git a/doc/environments/groupthm/groupthm.dtx b/doc/environments/groupthm/groupthm.dtx
index e20cdf9..e8d2e03 100644
--- a/doc/environments/groupthm/groupthm.dtx
+++ b/doc/environments/groupthm/groupthm.dtx
@@ -1138,6 +1138,51 @@
   }
 %    \end{macrocode}
 % \end{macro}
+% 
+% 
+%
+% \begin{macro}{\@@_add_to_sort_hook:n}
+%    \begin{syntax}
+%       \cs{@@_add_to_sort_hook:n}\ma{theorem group}
+%    \end{syntax}
+%		 
+%    Adds the theorem group into the sort hook to be restored later from it.
+%    This already uses the assumption, that we want to use the \cs{l_@@_group_clist}
+%    variable (which we do).
+%
+%    \begin{macrocode}
+\cs_new:Npn \@@_add_to_sort_hook:n #1
+{
+  \hook_gput_code:nnn { @@/groupsort }
+  { #1 }
+  {
+    \clist_put_left:Nn \l_@@_group_clist { #1 }
+  }
+}
+%    \end{macrocode}
+% \end{macro}
+% 
+%
+% \begin{macro}{\@@_sort_theorem_group_names:}
+%		 
+%     As explained briefly before, we first insert all theorems
+%     into the hook, clear the list, and then use the hook again.
+%     
+%     This then sorts the \cs{l_@@_group_clist} variable,
+%     which is also assumed to hold only defined theorem group names.
+%
+%    \begin{macrocode}
+\cs_new:Npn \@@_sort_theorem_group_names:
+  {
+    \hook_gremove_code:nn { @@/groupsort  }{*}
+    \clist_map_function:NN \l_@@_group_clist \__add_to_sort_hook:n
+    \clist_clear:N \l_@@_group_clist
+    \hook_use:n { @@/groupsort }
+  }
+%    \end{macrocode}
+% \end{macro}
+% 
+% 
 % \begin{macro}{\@@_declare_theorem_group_aux:nnnnn}
 %    \begin{syntax}
 %       \cs{@@_declare_theorem_group_aux:nnnnn}\{\meta{theorem group}\}\{\meta{prename tl}\}