My two BPs and my one BCI are in the same room. They are on different sides of the room, but not for health reasons, simply because that's the way the room setup allows.
If you practice strict hand hygiene in all dealings with your snakes, you should be okay. By this I mean wash hands with soap and water before and after ANY handling and do not share caging accessories without first giving the pieces a true disinfecting session. Taking the necessary precautions against cross contamination will go a long way in keeping your snakes healthy and thriving.
Also, be sure to remember that reptiles can harbour things that can be transmitted to humans, so it's important to practice the same handwashing techniques even if only handling one of the snakes....before and after ALWAYS.
Robbin