diff -u api.orig/api.module api/api.module
--- api.orig/api.module	2009-07-09 00:35:05.000000000 +0200
+++ api/api.module	2009-07-09 01:32:28.000000000 +0200
@@ -949,7 +949,14 @@
     return api_link_documentation($branch->documentation, $branch_name);
   }
   else {
-    return t('A main page for this branch has not been indexed. A documentation comment with <code>@mainpage {title}</code> needs to exist, or has not been indexed yet. For Drupal core, this is availiable in the <a href="http://cvs.drupal.org/viewvc.py/drupal/contributions/docs/developer/">developer documentation</a> in the contributions repository.');
+    // If no mainpage is defined, use a group's page instead
+    $result = db_query("SELECT documentation FROM {api_documentation} WHERE branch_name = '%s' AND object_type = 'group'", $branch_name);
+    if ($branch = db_fetch_object($result)) {
+      return api_link_documentation($branch->documentation, $branch_name);
+    }
+    else {
+      return t('A main page for this branch has not been indexed. A documentation comment with <code>@mainpage {title}</code> needs to exist, or has not been indexed yet. For Drupal core, this is availiable in the <a href="http://cvs.drupal.org/viewvc.py/drupal/contributions/docs/developer/">developer documentation</a> in the contributions repository.');
+    }
   }
 }