/**
* Saves the member groups
*/
private function SaveMemberGroups()
{
$selectedIDs = Request::PostArray('MemberGroup');
if ($this->page->GetGuestsOnly()) {
$selectedIDs = array();
}
$exIDs = Membergroup::GetKeyList(MembergroupUtil::PageMembergroups($this->page));
$this->DeleteOldMemberGroups($selectedIDs);
$this->SaveNewMemberGroups($selectedIDs, $exIDs);
}