I was using "shop" in the sense of the second of the short noun definitions ("the place where a specified kind of worker works : a worker's place of business") or number 5a under the long noun definitions ("a business establishment: office"). When used in that sense the type of business is usually used ("an I.T. shop"), but where it is implied or obvious it is often dropped. The dictionary doesn't list it as a colloquialism, but it is rather informal -- approaching the colloquial. As I used it I was intending to convey a group of I.T. professionals under the same management with a common set of policies, working on the same set of hardware and/or software.