[Plugin: Query Multiple Taxonomies] Query Custom taxonomies also with filter by other post type?

The QMT plugin looks great enabling faceted search through custom taxonomies.
Is there a way to have faceted search filtered not only by custom taxonomies, but filter via other custom post types as well?

I know that there is the posts2posts plugin, so is there a way to create relation between posts and then filter through it?

Thanks

http://wordpress.org/extend/plugins/query-multiple-taxonomies/