Can two buildings (separate owner - each building has its own utility xfmr) share same emergency generator but has its own ATS?
Interesting question. There are some requirements found in article 700 that would be harder to meet but not impossible in such a situation.
How do you propose to get the generator control wiring setup to monitor both locations?
Each building has its own ATS, so it doesn't matter, correct? The ATS will tell the generator what to do...
The code does allow for a separate service to be used as an emergency source so I can't see why this would not be acceptable.