They make a single feed of all those that hold the Badge and people can easily subscribe to it which I think could be very awesome for keeping up with all the users in a geographic area regardless of if they are a Community member.
Below is an example of the Homesteaders Badge page found here: https://steempeak.com/b/badge-131313
As you can see the 'Accounts Feed' is created by folks that are recipients of the Badge and the Subscribe button lets anyone subscribe to that feed.
I will look more closely at the Badges when I have all the Communities connected in.
:) Right now they are doing the first fifty free. You may want to expedite your research.