Syncing certain collections while keeping others local only

Let’s say there are two collections: c1 and c2. Objects in c2 can contain objects in c1 but not vice versa.

Is there a way to enable auto-sync for c2 but disable it to c1 and only sync c1 upon a button press? I’d like objects (and changes made to said objects) to remain local until a user clicks a “sync” button or something of the sort.