Advanced Taxomony question...

I've created a Custom post type called "Movie" -- and I want to use 2 different taxonomies... "Actors" and "Characters"

For example...
- Movie: When Harry Met Sally
- Actors: Billy Crystal, Meg Ryan
- Characters: Harry Burns, Sally Albright

That part is easy. The question I can't figure out is how to associate one taxonomy with another.

For example:
- "Billy Crystal" as "Harry Burns"
- "Meg Ryan" as "Sally Albright"

I thought about adding a custom field to the "Actors" taxonomy called "Characters they've played", but I'd like that to pull from my other taxonomy called "Characters".

Any ideas on how to relate one tax with another tax? I don't think you can make a taxonomy of a taxonomy.