I'd just open the whole thing in RB and do the MIDI there. It is much better for editing MIDI and generating certain sections of a given track, whether MIDI or RTs

You may even find another style of RT fits the bill better or you may need to resort to MIDI, and in RB it is easy to generate separate tracks of different styles in both MIDI and RTs.
Plus you can make many tracks (variations) of any instrument and cut/paste what you want to use from each variation easily too.
Just seems better suited for the job to me.

I do not work here, but the benefits are still awesome
Make your sound your own!