I wrote a simple web app for tracking zombies in your region. It requires a web server with shell access, and Python 3.4 or newer. You can grab a copy of it on GitHub.
As its name implies, it's been through two past zombie apocalypses already -- so it's pretty well-tested
If you're not technically inclined, I don't recommend setting this up yourself. Instead, have one designated person from your region host an instance and share it with the others. The app's web-based design makes it easy to set up this way.
If you have questions etc, feel free to file them on the issue tracker. You can reply to this post as well.
Happy zombie-ing!