How to make different user group with different colour fonts?

[deluxmall]

Following is the extract from the threadbit, I want to display different colour for different usergroup , how do i do that ?

<div class="smallfont">
<if condition="$show['threadratings'] AND $show['threadrating']"><span style="float:$stylevar[right]"><img class="inlineimg" src="$stylevar[imgdir_rating]/rating_$thread[rating].gif" border="0" alt="<phrase 1="$thread[votenum]" 2="$thread[voteavg]">$vbphrase[thread_rating_x_votes_y_average]</phrase>" /></span></if>
<if condition="$show['guestuser']">
$thread[postusername]
<else />
<font color="#9a0000"> Posted by :</font> <font color="#6f6f6f"> <span style="cursorointer" onclick="window.open('member.php?$session[sessionurl]u=$thread[postuserid]', '_self')">$thread[postusername]</span> </font>
</if>





</div>

--------------- Added [DATE]1258727099[/DATE] at [TIME]1258727099[/TIME] ---------------

How can i add a if condition ?