Best way to develop a broadcasting application?

Hi,

We want to develop a broadcasting application, there would be a main broadcaster on video, with a lot of chatters. There would also be some chatters going on webcam (6 max).

I'm still checking out NetGroups, IP Multicast, RTMFP Multicast, Fusion etc. but I am still lost. I also want to make sure that people who can't support RTMFP can be a part of the program by using RTMP, if that's possible right now to combine RTMP/RTMFP in such a big broadcasting application.

Thanks