So you are asking about making two copies of every rip. One on drive A and one on drive B. Correct? You are NOT trying to rip 2 CDs at one time from two different CD drives.
If it's two copies as I think, then I don't think MC can do this. At least not in a single step. The Rename Move and Copy files tool (part of MC) could probably be used in a multi step procedure, but I wouldn't do that either. I would make copies externally with a program designed to do that. In fact, that's exactly what I do with my music and video collections. I have a script that I run periodically that makes mirror copies of all of my media. It does so incrementally, so it only copies new or changed files. This makes it run in a short time, as opposed to making a full copy each time, which would take a very, very long time.
While I use a script, you could certainly use a graphical tool to do incremental copies.
Brian.