I'm glad you brought this up.  I just about had this figured out a couple of months ago, but then forgot about it.

The short answer is - yes, you can.  However, in MMM, it is not an easy and simple proceedure, but it can be done.

Since the explanation is fairly involved, I was forced to make a tutorial for it.  You can find it here...

http://www.magix.info/us/separating-imported-midi-tracks-in-mmm.online-training.413468.html

I hope this gives you what you need.  Good luck!