Well, I don't think you'd have to just have the guys on a particular sub-department showing up for a certain discussion. (Who knows, maybe someone with combat magic happens to have a WATER PURIFICATION ATTACK SPELL or something). I'm kinda more for aiming for things that can bring the whole department together, as well as specialised stuff, since that opens up opportunities. Possibly it could be a case of Abby stating what topics will be discussed on the channel beforehand, and then anyone who thinks they could contribute or might be interested can show up?