Querying a subgraph manually inside another subgraph?

Help
1

In user service:

type User {
  isPrivate: Boolean
  ...
}
type Query {
  user(userID: String): User
}

In social service.

type Query {
  followers(userID: String): [User]
}

In followers query, I want to return empty array if userID is a private and the requester isn’t approved follower of userID.

So, I can manually query user(userID) when resolving followers query in social service. And check if the user is private and if I’m the user’s follower.

Is there a better way to structure this? Ideally, I don’t want to manually query user(userID) in social service.

I almost want to have federation resolve parameters like:

type Query {
  # taking User object as parameter (but only isPrivate field from User object)
  followers(user: User { isPrivate }): [User]
}

And clients will query followers(userID) and have federation resolve the userID to User.