group fetch / data updates (class structure design)

What would be the best design for the following scenario?

I have a class that manages a bunch of NSManagedObjects. Inserting, deleting, fetching, etc. A viewController uses this object as the dataSource for a tableView. Thus every time the managed objects change (added, deleted or altered), the tableview has to reloadData().

To ensure that my class has the correct list of objects, it should fetch() the managedObjects after every delete or insert and notify any observers that its contents have changed.

So far this is all working nicely. However I would to limit the number of fetch() operations. Like NSView only draws once even though you called setNeedsDisplay multiple times. What is the best approach to do something similar to this?

It's kind of similar to a NSArrayController, but my class performs more functions in the backend while NSArrayController is more for binding views to the backend.