Having a lot of data in one "public" partition Realm


I know the question in a similar form has already been asked. Nevertheless I want to ask it myself because I couldn’t get my head around it.

I have an app wich uses a Team partition strategy for chats, a private (user) partition strategy for personal data and a “public” partition value for data that everyone can see but only the owner can write/change.

My first question is about the user. If I don’t want to share all the data from the user in the “public” partition, I would need to create two similar collections in my schema (one collection for the publicUser and on for the privateUser). Is there a simpler way than creating two collections that are actually the same (beside the values)?

I understand Realm that every Realm partition I open in the app, saves all the data from that partition on the device. That would mean for my public partition, that every user that creates data in the public partition, would force all the other users to save the created data on their local device as soon as the app opens the “public” Realm.

If that’s correct, then how is an app with Realm Sync and MongoDB like Airbnb possible, which has a lot of public data that can’t be stored locally on devices. Is there a solution to have an only Online partition OR to never save data on the device when there is only a read permission?