Users want to see other users in the groups they belong to
and annotations each of these users have made and shared with a
group. This will help them decide how to share annotations with
their groups.

https://trello.com/c/rSUQLuos/294-as-a-user-i-want-to-be-able-to-find-out-who-is-a-member-of-a-group-i-m-in