user online group

[rudzstyle]

good morning, i'am new here and new about php script, i'am still at college so i make my own web project and i implement this phpfreechat aplication there but my lecture still want me to improve it then she told me for make a group at that chat.
it used to be for if in the room has a lot of member and u must find some1 there for some reason u need a lot of time for find him. may be group it by the area where he/she belong.
in my case i need make it to be group where the city of the user online.

please help me, thanks for reading my request.
regards
rudzstyle