Another Boa Housing Question...

Here is the situation. 1 rack in one room housing a BCL and a Cay Caulker BCI and 1 rack in another room housing 1 BP. I know that BCC/BCI's are always potential carriers of IBD so the question is this. When introducing another snake such as a BRB, Rosy, or Sand Boa, after quarantine, which rack would you house them in? From what I have found so far is that it would make more sense to house them in the rack with the BP. I would just like to get some opinions or recommendations on this. Thanks...