A group (co-)owners can add new users to the group. It may be sufficient for beaker command to accept one user at a time. To add multiple users at once, user may create own script.
This is part of http://beaker-project.org/dev/proposals/enhanced-user-groups.html
*** Bug 908178 has been marked as a duplicate of this bug. ***
On Gerrit: http://gerrit.beaker-project.org/#/c/1944/
Verified. bkr group-modify --add-member="username" <mygroup> & bkr group-modify --remove-member="username" <mygroup> can successfully add/remove member to/from mygroup as I am the owner of the group. beaker-client version: beaker-client-0.12.1-1.git.138.df77d66.el6eng
Beaker 0.13.1 has been released.