Restrict access to repositories to people in team

In Bitbucket repository user and access groups the add user box auto completes with all the Bitbucket users in the world.
We need to be able to restrict Bitbucket repository access to users in the team (or via email domain) so nobody outside our team can accidentally be granted access. The UI shows if a user is a team member but does not restrict it to these users.

It would be great if there was some way to only show members from the team to be added into a group or repo.