Each entity is a different person. Banks are required to aggregate if transactions are by the same person. They are also required to aggregate if transactions are on behalf of the same person.
Two entities with the same owners and signatories are not the same person. Their transactions are not subject to aggregation.
There is FinCEN guidance to the effect that if the entities are not operated separately; e.g. transfers are made between them to cover payrolls etc. then their transactions might be subject to aggregation. That's the exception, not the rule.
In this world you must be oh so smart or oh so pleasant. Well, for years I was smart. I recommend pleasant.