I'm using the GET /accounts/{accountId}/eventregistrations API to retrieve the list of registrants. I also have a large number of guests. The only way to retrieve detailed guest info is to make individual calls to the registrant API, find whether they have any guests then make individual calls for each guest.

Is there any way to use a single API call to retrieve all registrant and guest info in one call, to speed things up and make fewer calls, maybe using $filter? Based on the SWAGGER API reference it doesn't seem possible, but doesn't hurt to ask.