From what I've gathered from reading on quarantine is that different rooms do not really matter. If it's can spread through the air, anything in the same house is going to catch it. Most things will be transferred by contact so as long as you don't handle your quarantine animals and then go handle yours without changing clothes and washing hands (and of course don't use the same tongs and such) you should be fine. I keep my quarantine animals in a tank in a different the room from my others, just to remind myself and others of the quarantine. If they are from the same breeder I would quarantine together, if from different breeders, I'd personally separate.