The basic question is "can every client have a data channel to every other client in a room". The answer is yes. You can try this with the data channel messaging demo. I think Webrtc supports up to 100 data channels per client.
Beyond that, it would be up to you to read in a file on one client, partition it into pieces, label the pieces, and then send the pieces to the other peers, and coordinate the ensuing communication in such a way that it behaved like a torrent.