Add multiple user to UNIX group in one line

On *Centos 6.5* (and probably any) linux, I can create a group: sudo groupadd mygroup and add several users to it: sudo usermod -a -G mygroup userA sudo usermod -a -G mygroup userB sudo usermod -a -G mygroup userC The number of users in my particular case is 20. How can I use a one-liner like: sudo usermod -a -G mygroup userA userB userC Even using for loop would be fine, but I'm not a bash specialist, so wondering.