you can certainly add some code in the postbit legacy under $posts to the effect of
HTML Code:
<vb:if condition="is_member_of($bbuserinfo, 1,2,3)"><img src="/images/yourgroup.gif" border="0" /></vb:if>
or if the icons are the same number as the usergroup you could do this
HTML Code:
<vb:if condition="is_member_of($bbuserinfo, 1,2,3)"><img src="/images/$bbuserinfo[usergroupid].gif" border="0" /></vb:if>
or whatever the group or social group is, just food for thought