We don't have to discuss their relation to you, but I've dealt with enemies and rivals alike before, so I think there must be a solution.

[He has to pause to cough, but it's brief, and he's leaning back in his chair.] Depending on the type of people they are, you can leave surprises around the rooms for them so they get annoyed. The solution to irritating roommates may be to become the irritating roommate, I think. But that's just one path.