I believe there have been a couple of earlier discussions about this.
There is no "clean" way to do it, but what you end up with depends on
the software you use to convert the MIDI file and how you set it up
(beat quantizations, etc.).

Also, with heavily edited or arranged "duet" scores you need to divide
the notes up between hands (or pianos) yourself if you want something
playable.  I import into Finale and work from there, though it is
time-consuming.  Some use an intermediate beat quantization software.
It's a lot of work, no matter what.

Jeff Taylor