diff --git a/doc/environments/groupthm/groupthm.dtx b/doc/environments/groupthm/groupthm.dtx
index 6cbcf0d..0a3abcc 100644
--- a/doc/environments/groupthm/groupthm.dtx
+++ b/doc/environments/groupthm/groupthm.dtx
@@ -1588,6 +1588,7 @@
       }
       {
         \tl_log:n { Removing ~ definition ~ of ~ #2 ~ '#3'. }
+        \tl_log:n { Declarator ~ was ~ #1. }
         #5 { #3 }
       }
 %    \end{macrocode}
@@ -1708,7 +1709,6 @@
   {
     \cs_set:Npn \@@_map_aux:n ##1
       {
-        \def \declarator { ##1 }
         \cs_new:cn { #2 }
           {
             #3
@@ -1733,7 +1733,7 @@
 %    \begin{macrocode}
 \@@_wrap_multiple:nnn
   { new, renew, provide, declare }
-  { groupthm_ \declarator _group:nn }
+  { groupthm_#1_group:nn }
   {
     \@@_set_normalized_keys:nnn { ##1 } { theoremgroup } { ##2 }
     \use:c { groupthm_#1_group:nVVVV }
@@ -1759,16 +1759,17 @@
 %     and upper-case versions of the current declarator.
 %
 %    \begin{macrocode}
+\cs_new:Npn \@@_new_document_command:Nnn #1 #2 #3
+{
+  \NewDocumentCommand { #1 } { #2 } { #3 }
+}
+\cs_generate_variant:Nn \@@_new_document_command:Nnn { c n n }
 \cs_new:Npn \@@_wrap_multiple_document:nnnn #1 #2 #3 #4
   {
     \cs_set:Npn \@@_map_aux:n ##1
       {
-        \def \declarator { ##1 }
         \def \Declarator { \text_titlecase_first:n { ##1 } }
-        \exp_args:Nc \NewDocumentCommand { #2 } { #3 }
-          {
-            #4
-          }
+        \@@_new_document_command:cnn { #2 } { #3 } { #4 }
       }
     \clist_map_function:nN { #1 } \@@_map_aux:n
   }
@@ -1785,7 +1786,7 @@
   { \Declarator TheoremGroup }
   { O{} m }
   {
-    \use:c { groupthm_ \declarator _group:nn } { ##1 } { ##2 }
+    \use:c { groupthm_#1 _group:nn } { ##1 } { ##2 }
   }
 %    \end{macrocode}
 % \end{macro}
@@ -2070,7 +2071,10 @@
 %    \end{macrocode}
 % Now, retrieve the group properties, by writing these into the hooks
 %    \begin{macrocode}
-    \clist_map_function:nN { #2 } \@@_use_group:n
+    \@@_flatten_groups_hierarchy:nN { #2 } \l_@@_group_clist
+    \clist_map_function:NN \l_@@_group_clist \@@_use_group:n
+    \tl_log:x { Flattened ~ groups ~ '#2' ~ to ~ '\clist_use:Nn \l_@@_group_clist {,}' ~ when ~
+                defining ~ theorem ~ '#1' }
 %    \end{macrocode}
 % Execute the hooks, so that local variables will get modified according to the groups
 % and in the order that were specified for the hooks.
diff --git a/doc/environments/groupthm/groupthm.sty b/doc/environments/groupthm/groupthm.sty
index b6cddf7..f65811f 100644
--- a/doc/environments/groupthm/groupthm.sty
+++ b/doc/environments/groupthm/groupthm.sty
@@ -257,6 +257,7 @@
       }
       {
         \tl_log:n { Removing ~ definition ~ of ~ #2 ~ '#3'. }
+        \tl_log:n { Declarator ~ was ~ #1. }
         #5 { #3 }
       }
     \cs_if_exist:NTF #4
@@ -304,7 +305,6 @@
   {
     \cs_set:Npn \__groupthm_map_aux:n ##1
       {
-        \def \declarator { ##1 }
         \cs_new:cn { #2 }
           {
             #3
@@ -315,7 +315,7 @@
 
 \__groupthm_wrap_multiple:nnn
   { new, renew, provide, declare }
-  { groupthm_ \declarator _group:nn }
+  { groupthm_#1_group:nn }
   {
     \__groupthm_set_normalized_keys:nnn { ##1 } { theoremgroup } { ##2 }
     \use:c { groupthm_#1_group:nVVVV }
@@ -325,16 +325,17 @@
       \l__groupthm_mapname_clist
       \l__groupthm_thmtools_clist
   }
+\cs_new:Npn \__groupthm_new_document_command:Nnn #1 #2 #3
+{
+  \NewDocumentCommand { #1 } { #2 } { #3 }
+}
+\cs_generate_variant:Nn \__groupthm_new_document_command:Nnn { c n n }
 \cs_new:Npn \__groupthm_wrap_multiple_document:nnnn #1 #2 #3 #4
   {
     \cs_set:Npn \__groupthm_map_aux:n ##1
       {
-        \def \declarator { ##1 }
         \def \Declarator { \text_titlecase_first:n { ##1 } }
-        \exp_args:Nc \NewDocumentCommand { #2 } { #3 }
-          {
-            #4
-          }
+        \__groupthm_new_document_command:cnn { #2 } { #3 } { #4 }
       }
     \clist_map_function:nN { #1 } \__groupthm_map_aux:n
   }
@@ -343,7 +344,7 @@
   { \Declarator TheoremGroup }
   { O{} m }
   {
-    \use:c { groupthm_ \declarator _group:nn } { ##1 } { ##2 }
+    \use:c { groupthm_#1 _group:nn } { ##1 } { ##2 }
   }
 \cs_new:Npn \groupthm_declare_group_rule:nnnn #1 #2 #3 #4
   {
@@ -467,7 +468,10 @@
     \hook_gremove_code:nn { __groupthm/suffix }{*}
     \hook_gremove_code:nn { __groupthm/mapname  }{*}
     \hook_gremove_code:nn { __groupthm/thmtools }{*}
-    \clist_map_function:nN { #2 } \__groupthm_use_group:n
+    \__groupthm_flatten_groups_hierarchy:nN { #2 } \l__groupthm_group_clist
+    \clist_map_function:NN \l__groupthm_group_clist \__groupthm_use_group:n
+    \tl_log:x { Flattened ~ groups ~ '#2' ~ to ~ '\clist_use:Nn \l__groupthm_group_clist {,}' ~ when ~
+                defining ~ theorem ~ '#1' }
     \hook_use:n { __groupthm/prefix }
     \hook_use:n { __groupthm/suffix }
     \hook_use:n { __groupthm/mapname }