Thanks for the help guys!
I decided in the end to record the song 3 different times and put the results together in Camtasia (software for recording what is on the computer screen) because I wanted the music for the 3 different parts to appear simultaneously. I used the tick marks at the beginning to line up the 3 recordings as best I could (it is not perfect).
I did unfold the song. The second time I recorded I added 8 empty bars at the beginning, and muted the accompaniment for all but the last 8 bar. I also changed the colour of the background each time.
For the 3rd repeat I just had to add another 8 bars at the start.
I found it sounded better to use exactly the same midi for all three.
https://youtu.be/sj7DgDHW8V4