Batch get users from API


I am using the Auth and User service to handle login, and user related functionality in my app, but I am wondering if there is a way to get a batch of users from the API service? I know there is list, get, put, and so on, but I can’t find a way to get a batch based on their IDs. It seems like it is incredibly inefficient if I had to do a get request for every user that I would need, also seems extremely inefficient to grab a list of every single user in the entire app, and then filter through all of them for a sublist that would match an array.
Essentially a user can have a “watch” list, where they are “watching” other users, that information is saved as an array in the custom user object, so I would have an array of user IDs in an array. That list could get rather large if a user is so inclined to add enough users to their “watch” list, so making 1 api call for every user in that list is not an option, conversely making a call to get every single user in the entire app and then foreaching through them to get the ones in the users watch list seems extremely inefficient too. Does anyone know of a better way to handle this, or a way to batch get from the API? Please. Thank you.