Open includes/functions.php

FIND

Code:

      'SITE_LOGO_IMG'         => $user->img('site_logo'))
   );


AFTER ADD

Code:

    if ( !function_exists('group_memberships') )
    {
        include($phpbb_root_path . 'includes/functions_user.'.$phpEx);
    }
    $groups = group_memberships(false,$user->data['user_id']);
    foreach ($groups as $grouprec)
    {
        $template->assign_vars(array(
        'S_GROUP_' . $grouprec['group_id'] => true
        ));
    }


then use the switch like so

Code:

<!-- IF S_GROUP_2 -->some stuff here<!-- ENDIF -->