Let team member see which member is currently in a group of team (BB-7859)

My team account members cannot see the detail of a groups of my team
account. As I described in
https://groups.google.com/forum/?fromgroups=#!topic/bitbucket-users/02rMewNCiAs

Since they cannot see who in which group, they even don't know what groups
they belong to, if I didn't tell them.
That would be sometimes confused when a repo admin want to setup the access
right of a repo.