How about a separate forum for doping talk? It would probably see more action than the track, mtb, and cross forums combined. Ok, so I'm mostly joking but it really sucks around the road forum these days.
You would do better by developing a community culture looks down upon thread hijacks. As long as doping discussions do not get inserted into threads where they don't belong then the forum will be okay. Even if a doping forum is set up, you will still have to deal with thread hijacking, thread moving, doping trolling, etc.
There currently is not enough traffic to split forums anyway.