Once you have found the schematic sheet to work on (take a look at the Hierarchy Walker script that is discussed here : https://communities.mentor.com/docs/DOC-1345#comment-1572 )
All you need to do is activate it :
Snippet from that document :
The PushPath method will also activate your 'Block' (= your schematic sheet), so all you need is to do your magic in line 24, where the above code iterates through all component objects on that page.
I hope this helps
This ended up working for me.