[dismas]

Try this (I haven't tested it to see if it works but I think it will)

Find in your post bit template

<if condition="$post['usertitle']"><div class="smallfont">$post[usertitle]</div></if>

replace with:

<if condition="$post['usertitle']"><div class="smallfont"><if condition="is_member_of($bbuserinfo, X, Y, Z)"><font color="#FF00FF">$post[usertitle]</font><else />$post[usertitle]</if></div></if>

Replace the X, Y, Z with the id numbers of the usergroups that you want a specific color for. And change the #FF00FF to whatever color you like