I am trying to implement teams of player characters. Creating a group of characters works fine and shows up correctly in the PlayFab console. But when I try to use ListMembership on the character from the Unity SDK, it returns an empty list. I figured out that this is because the default group policy allows only members of the group to call this. Changing the policy to give everyone read access fixed it and I can see the group.
However, this is not a solution because the same applies to write requests like RemoveMembers and AcceptGroupApplication, and we cannot make those public obviously. What we really need is a group policy that gives access to the player that owns the character in the group. But I cannot find any documentation on the format of the Principal field in the policy other than "you can use * to match anyone".
Is there any documentation on the policy format? What is the recommended way of doing groups of characters?