D.C Nets

some people mentioned that they want to set up local (neighborhood) networks and that they are "ideal" for making D.C. Nets with. I have a question about DC Nets. Is there anyway to use a DC Net to create sessions? The DC Net protocol is bit based right? So if you set up a session how do you tell which bits came from one person and belong to one session, and which came from another and belong to another session? Especially since the whole point of a DC Net is to make it undetectable where the bit originated from. Also once you solved that, what is to stop someone else from injecting bits into your session? ...