That is tricky.
You could do the following:
open viewtopic.php and in line 29 enter
function GroupPips($groupid) {
$group2pip = array("1"=>6,
"2"=>3,
"3"=>2,
"4"=>1,
"5"=>4,
"6"=>5);
if(!array_key_exists($group2pip,$groupid)) return '';
else {
for($i = 1;$i <= $group2pip[$groupid];$i++) {
$outpips .= '<img src="img/pip.gif" alt="" />';
}
return $outpips;
}
}
Then, find around line 216
$username = '<a href="profile.php?id='.$cur_post['poster_id'].'">'.pun_htmlspecialchars($cur_post['username']).'</a>';
and after that, add
$username .= '<br/>'.GroupPips($pun_user['g_id']);
Note:
In the function GroupPips you have an array group2pip.
The keys represent the group id of your groups, the values the number of pips you want to show for it.
Note 2 I haven't tested all this so take it as an idea, not a complete recipe.