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If you do a street address and cityname search in Google Maps, you'll get a listing of all the businesses located at that address. It's likely that those businesses aren't hurting each other by sharing the same building. It happens all the time.
On the other hand, if you have a dozen widget companies all located in the same suite at the same address, Google might not want to list them all in the same map + 10 listing for [widget placename] up at the top of Google's regular search, but that's just an assumption I'm making. Google's local filters may not yet have evolved that far.