I’m just gonna chime in here by saying that the lack of this functionality has been the bane of our existence for years.
No way to fetch multiple specific objects and no way to include details of orgs/persons etc. when fetching deals.
Here’s the workaround we’ve been using extensively:
Have the program create a filter that finds these organisations by the filters endpoint.
Fetch your orgs/deals/whatever from that filter.
Delete the filter.
This is all possible via the api, although obviously not useful in every use case.
It is also kind of inefficient, fragile, slow and prone to resulting in weird behaviour (like random filters that got left behind cause they weren’t deleted for whatever reason).