[Xenon]

well, the usergroupid isn't saved within the threadtable, so you have to include the usertable to the query:

in forumdisplay find this:

PHP Code:

$getthreadids=$DB_site->query("
    SELECT
    ".iif($sortfield=="voteavg",$votequery,"")."
        thread.threadid
    FROM thread
    WHERE thread.forumid = $foruminfo[forumid]
        AND thread.sticky=0
        AND thread.visible=1
    $datecut
    $limitothers
      ORDER BY sticky DESC, $sortfield $sqlsortorder
      LIMIT ".($sel_limitlower-1).",$perpage"); 


and change it to:

PHP Code:

$getthreadids=$DB_site->query("
    SELECT
    ".iif($sortfield=="voteavg",$votequery,"")."
        thread.threadid    FROM thread
              LEFT JOIN user ON (thread.postuserid = user.userid)
    WHERE thread.forumid = $foruminfo[forumid]
        AND thread.sticky=0
 ".iif(in_array($bbuserinfo[usergroupid], array(5,6,7,16)), "", "AND user.usergroupid != 16 ") . "
        AND thread.visible=1
    $datecut
    $limitothers
      ORDER BY sticky DESC, $sortfield $sqlsortorder
      LIMIT ".($sel_limitlower-1).",$perpage");