Index: fieldgroup.module
===================================================================
--- fieldgroup.module
+++ fieldgroup.module
@@ -61,6 +61,11 @@
 function fieldgroup_edit_group($content_type, $group_name) {
   $groups = fieldgroup_groups($content_type);
   $group = $groups[$group_name];
+  
+  $group_options[0] = t('Top');
+  foreach ($groups AS $name => $item) {
+  	$group_options[$name] = $item['label'];
+  }
 
   if ($group_name == 'add_group' && arg(6) != 'edit') {
     //adding a new one
@@ -99,6 +104,12 @@
     '#title' => t('Collapsed'),
     '#default_value' => $group['settings']['collapsed'],
   );
+  $form['settings']['parent'] = array(
+    '#type' => 'select',
+    '#title' => t('Parent Group'),
+    '#default_value' => $group['settings']['parent'],
+    '#options' => $group_options
+  );
   $form['settings']['#tree'] = TRUE;
   $form['description'] = array(
     '#type' => 'textarea',
@@ -242,18 +253,36 @@
       node_get_base($form['#node']) == 'content') {
 
     foreach (fieldgroup_groups($form['type']['#value']) as $group_name => $group) {
-      $form[$group_name] = array(
-        '#type' => 'fieldset',
-        '#title' => t($group['label']),
-        '#collapsed' => $group['settings']['collapsed'],
-        '#collapsible' => $group['settings']['collapsible'],
-        '#description' => $group['description'],
-        '#weight' => $group['weight'],
-        '#attributes' => array('class' => strtr($group['group_name'], '_', '-')),
-      );
+      if ($group['settings']['parent'] && arg(0) != 'admin') {
+      	$form[$group['settings']['parent']][$group_name] = array(
+          '#type' => 'fieldset',
+          '#title' => t($group['label']),
+          '#collapsed' => $group['settings']['collapsed'],
+          '#collapsible' => $group['settings']['collapsible'],
+          '#description' => $group['description'],
+          '#weight' => $group['weight'],
+          '#attributes' => array('class' => strtr($group['group_name'], '_', '-')),
+        );
+      } 
+      else {
+        $form[$group_name] = array(
+          '#type' => 'fieldset',
+          '#title' => t($group['label']),
+          '#collapsed' => $group['settings']['collapsed'],
+          '#collapsible' => $group['settings']['collapsible'],
+          '#description' => $group['description'],
+          '#weight' => $group['weight'],
+          '#attributes' => array('class' => strtr($group['group_name'], '_', '-')),
+        );
+      }
       foreach ($group['fields'] as $field_name => $field) {
         if (isset($form[$field_name])) {
-          $form[$group_name][$field_name] = $form[$field_name];
+          if ($group['settings']['parent'] && arg(0) != 'admin') {
+            $form[$group['settings']['parent']][$group_name][$field_name] = $form[$field_name];
+          }
+          else {
+          	$form[$group_name][$field_name] = $form[$field_name];
+          }
           unset($form[$field_name]);
         }
       }