static function FindPageGroup(Page $page)
    {
        $currPage = $page;
        $result = null;
        do 
        {
            $result = $currPage->GetUserGroup();
            $currPage = $currPage->GetParent();
        } 
        while (!$result && $currPage);
        if (!$result && $page->GetSite())
        {
            return $page->GetSite()->GetUserGroup();
        }
        return $result;
    }