[ForceHSS]

If you turn on html allowed in a section from what I remember it opens that section up to all groups to use html I might be wrong and cant checked this now to confirm it so you might need it coded. Maybe someone else can confirm this. Maybe a plugin has been made already try a search see what comes up
not sure if this will work for your version
Try this for the bbcode_parse plugin

PHP Code:

global $post; 
$perms =& $post['permissions']; 
if (!$perms) 
{ 
    $perms = fetch_permissions(0, $post['userid'], $post);  
} 
// Was this post made by an allowed Usergroup member? 
if ($perms['allowhtmlpermissions'] & $this->registry->bf_ugp_allowhtmlpermissions['canposthtml']) 
{ 
    // This is an allowed post so parse HTML. 
    $dohtml = '1'; 
}