Conditional Question

[Powlo]

I have some code here that is added into attachment.php to force users to reply to a thread before they can download the attachment. How can i use a conditional so 2 or 3 of my usergroups can skip this?

   if ( !$vbulletin->db->query_first ( "SELECT postid FROM " . TABLE_PREFIX . "post WHERE userid='".$vbulletin->userinfo[userid]."'  AND threadid=$threadinfo[threadid]" ) ) :   
                        eval('print_output("' . fetch_template('MARCO1 Cant See Attach') . '");');   
                endif ;

This is from a modification from vb.org by marco1 but im not getting much help in that forum but im sure a simple condition wrapped around this would do the trick but i dont know how i would code it.

Thanks in advance.