wish: could composite store info about datastores that have been changed?

I wrote code that updates datastore changes to Web too. I'm using 
several composite stores for different purposes. One composite is for 
reading (because that you can do from the Web directly) and some others 
for writing and updating. However, as far as I understand the composite 
does in no way support finding out which stores included in the 
composite need refreshing e.g. which stores in the composite changed 
when I asserted something.

Would it be possible to keep track and tell which one of stores in the 
composite need refreshing after the composite RDF was modified by doing 
assertions, modifications etc. to the composite? This would help to 
optimize some Web traffic.

I understand that when I use http to upload something to Web it may be 
difficult to find that out but if I know which stores were written 
locally with RDF store APIs I can keep track of the Web modifications 
and save some unnecessary Web reading and uploading.

Naturally it would also help if composites and other datastores would do 
the uploading in the Web without my code. But that is a bit more work. 
Has someone done this already as a package?

Marja