How to deal with model values that are specific to a parent via a relationship

I have a model "Group" which owns "GroupMember" models via a HasMany relationship.

The "GroupMember" has an attribute "isAdmin" which indicates if that member is an admin of the group.

When i view a list of "GroupMember" ember-data tries to refresh those items from the API with a GET request of /groupMembers/{id} for each item.

The problem is i have no idea what group that member is being refreshed for in order to set the "isAdmin" value. It seems like the request should be /group/{group_id}/members/{member_id}.

Sorry if this doesn't make much sense. Im having trouble wording it. Let me know what i can do to clarify.