ansible/ansible — pull request #1750 by dhozac (2012-12-11 07:41:44+00:00)
Title: Allow intersecting host patterns by using &

This allows patterns such as webservers:!debian:&datacenter1 to target
hosts in the webservers group, that are not in the debian group, but are
in the datacenter1 group. It also parses patterns left to right, so you
can combine things such as
webservers:&datacenter1:mailservers:&datacenter2 to target hosts in the
webservers group in datacenter1, and the mailservers group in
datacenter2.