Choosing blogs to display posts from

How can I choose blogs to display posts from using 'Post Indexer' and 'Recent global posts'?

I need multi network site, some kind of city.state.country.com.
In state.country.com I would like to display posts from cities belonging to that specific state.
In country.com I would like to display posts from my entire network.

It would be also very helpful if I could filter displayed posts by category or tags.

Thank You