"some companies are producing IM clients that act as a front end to the different networks. One such product is Trillian Pro, from Cerulean Studios, which allows you to connect to ICQ, AIM, MSN Messenger, Yahoo! Messenger and IRC networks through a single interface. It should be noted that these clients do not offer interoperability between the various IM networks — just a unified interface through which to access them. If you are looking for true interoperability then hub software, which can actually route messages between networks, is required."
Which software can be used as hub software and enable group chat with AOL/MSN/YAHOO users?
So all users can respond to eachother?