I have one herp room (a former dining room) and yes, my snakes are all in the same room; 5 BPs and one BCI. It would probably be useless to house them in seperate rooms anyway, since our floor of the house has an open floor plan, and any bacteria that'd be airborne would travel around, anyway. But I always handle my BCI last, if I am handling or cage-cleaning more than once in a day, and take precautions in between any animal handlings; wash hands good, etc.