I realize this is an old thread, but I thought it was in interesting question so here I am replying.

An important aspect of quarantine that is often over looked is the order in which you work with your snakes. Always work from "clean" to "dirty" and shower before going back to "clean." Generally the established collection is considered "clean" and the snakes in quarantine are "dirty." So you always feed, water, cage wash, etc the "clean" group before working with the "dirty" group. After you've done your chores for the "dirty" group, don't handle the clean group or any equipment associated with them until you've showered and changed clothes.

In your case where you have two groups of snakes in quarantine, you have "python dirty" and "boa dirty." Because the boas could potentially carry IBD without any signs, I would consider them "dirtier" than the "dirty pythons." So the safest thing to do would be have separate dedicated equipment for the two groups and work with the pythons before the boas. It doesn't matter if they are in the same or different rooms (or garages) if you follow these precautions. Hope that makes sense!