A fool's errand? Post indexer query

Ok, this is a bit complicated so bear with me.

I have a Multisite install where each individual site has it's own business listing directory.

right now, the business listing directory i'm using is true-multisite compatible, in that, it uses a separate table for storing it's site's listing information on a per site basis.

So far so good.

I still want to maintain that separation. However, I would like to create a setting for all the site's listing post type that would allow the listing owner to share that particular listing (or a collection of listings) with the rest of the multisite network.

I'm wondering: does the post indexer allow you to look for such a setting? can it ignore posts that have specific fields selected or is there a better way to do this?s