In Poland, there's an idiom that I've recently fallen in love with. Nie mój cyrk, nie moje małpy . . . literally, "not my circus, not my monkey;" figuratively, "not my problem."
I guess monkeys are "problems" in Poland, and circuses are where "problems" come from. If it's not your monkey, and it's not even from your circus, then it's not your problem.
(Not that I'd ever use this in a truly serious situation . . . but I'm betting there'll be a few opportunities to call upon this idiom around the office.)