Notifying Someone Else on Entering Region

Out of curiosity, is there anyway to notify someone when a user enters a particular region?

For example: Let’s say someone enters a particular beacon region within a building, is it then possible to notify someone else (in the same building) that that region has been entered?

One possible way is to have a notification post a message when someone enters a region and have a listener on the other side. Or perhaps have a remote notification trigger when a user enters the region as well. Just speculating…

Not sure if that’s what @phillydev716 meant: I personally would introduce a “middleman”—a backend to which you post the fact that somebody entered a region. This backend can then issue e.g. a push notification to other people using the app, or maybe the app is simply polling the server about any new enters etc.

Thanks guys, that’s kind of what I thought but was hoping there might be an easier solution.