I know there are ways to hide (or disallow viewing of to certain groups.) the profiles, so something similar should be easy enough to do with the user list.

depends on how down and dirty you want it.. if you want a menu in your control panel that you can click on and select and deselect groups you will have to write alot more code persay than if all ya want to do is write a little code in showmembers.php or online.php in which case in those files dependimg if you meant hide the userlist or the who's on line list and add some code basicaly stating<br /><br />under<br /><br />$html = new html;<br /><br />add something like<br /> if (strpos($user['U_Groups'], '-4-') == false && strpos($user['U_Groups'], '-5-') == false) {<br /> $html -> not_right ("Sorry No Peeky",$Cat);<br /> }