Related posts across blogs

Hi,

i'm sure anyone knows one of the wonderful related posts plugins around the world. My favorite is YARPP (yet another related posts plugin) as it works well, it's tweakable to fine tune the way it finds related posts and it caches its result which is good in performance terms.

But i wonder if there's a way to have this function across multiple blogs? I'm currently setting up a bigger site that uses multiple blogs to divide it's content into severaly regions. Having related posts across these blogs would be a real nice feature here and i think other could make use of this, too.

Thanks for helping!
Frank