[MarkFL]

If you wish to remove the link button from the toolbar, create a plugin hooked at "editor_construct" and use the Plugin PHP Code:

PHP Code:

if (is_member_of($vbulletin->userinfo, array(X, Y, Z)))
{
    $k1 = 0;
    $k2 = 0;

    foreach($this->config['toolbar'] AS $arr_1)
    {
        if (is_array($arr_1))
        {
            foreach($arr_1 AS $arr_2)
            {
                if ($arr_2 === 'Link')
                {
                    unset($this->config['toolbar'][$k1][$k2]);
                    break 2;
                }

                $k2++;
            }
        }

        $k1++;
        $k2 = 0;
    }
} 


Replace "X, Y, Z" with the comma-delimited list of usergroupids of those groups for which you wish to remove the link button.