here's something you can do to keep all people from joining a common room at login,
this will depend on your user set up, but in the index add $params["channels"] = array($_SESSION['user']);
meaning whatever this is $params["nick"] = $_SESSION['user'];
put the same thing in the channels array, then when a user logs in for the first time they land in their user name room
this works great if you have rooms already defined from the template, after landing in there room people cannot see that they have logged in and they can use the /invite command or /join command
here's an example http://spfldmo.com/sites/chat/
log in as demo demo or sign up for a new user