[Dismounted]

Just make $group_ids an array, and then in the query where you fetch user data, fetch the usergroup IDs as well, then just use this:

PHP Code:

$membergroupids = explode(',', $rut_row['membergroupids']);

foreach ($membergroupids AS $id)
{
    if (in_array($id, $group_ids))
    {
        $userok = true;
        break;
    }
    else
    {
        $userok = false;
    }
}

if (!in_array($rut_row['usergroupid'], $group_ids) AND !$userok)
{
    // user is not allowed
}