Sometimes we need to define several unrelated projects to a team, each project having several jobs.

One solution is to duplicate the groups which we want to avoid, and the other is to have a single group with a slightly more complex regexp.

Another solution could be multiple patterns:

^build_my_first_project_.*
^test_my_first_project_.*
^build_the_second_one_.*
^test_the_second_one_.*

Instead of:

^(build|test)_(my_first_project_|the_second_one_).*

Not everyone in the team is comfortable with (even simple) regular expressions, so we could trade a bit of duplication for readability.

I stole the idea from this plugin:
https://wiki.jenkins-ci.org/display/JENKINS/Build+Blocker+Plugin#BuildBlockerPlugin-Howtouse