Sorry, no; this is OR character matching (like Trick or Treat, if you're familiar with that). You are of course welcome to mention the character combinations you like in your optional details, but there's no way to guarantee yourself a match on two characters.

(For what it's worth, I have at various points in the past considered the idea of using the same sort of overloading of character tags that some other exchanges employ to allow matching on characters or ships, as you suggest, but reluctantly came to the conclusion it would tip the nominations and sign ups stages over from Really Quite Complicated to Too Complicated.)