How to detect collection updates in mongodb when triggered by a different application

I have two Meteor applications (A and B) using the same mongodb. I am updating the Collection.MyEntries from a method in application A.

I need to detect this update and retrieve the updated document on the SERVER in application B. How can I do that?

I have thought about collection hooks, but this wont work since the insert is in application A (which will not trigger a hook in application B). Also I dont need the data on the client in application B (then I would have used subscribe/publish observe).

I could run a cron job every x seconds and check but this does not sound like an elegant solution. Would appreciate any hints what is best practice here.