I need to find a way to get the Part Markers from a RealBand session as if I save it as ABC or MusicXML there are no Part Markers to say where the different playing styles are in the source files.
I can get the Part Markers from a Chord Chart Converter for MyJazzBand that converts the SGU to .mjb text file,
but if I save a real time signature in RealBand as SGU it will dumb it down and stuffs up the Part Markers for the 4/4 limitation.

You would have to save the A style as one RealTimeSignature UserTrack and the B as another.
When you generate it up you can select what bars have what UserTrack and the script will join them together as one wav then import it. You could also regenerate any sections you like. It could have a drag n drop from the script's GUI to drag n drop the new section in overwriting the existing bar/s.
It could the also use real time signature tracks created in REAPER by reading the region .csv

It's the only way I can see to get Real Time Signatures.

SGU to .mjb text file
Code:
Name: Hard Rock with 80s Synth RealTracks Demo
Meter: 4/4
Style: Swing
Key: C
Tempo: 120
Chorus: bars 1 to 96 (repeat 1 times)
Sections: 1A 9B 17A 25B 33A 41B 49A 57B 65A 73B 81A 89B 97A
| G/C C | G/C C | G/C C | F G |
| G/C C | G/C C | G/C C | F G |
| Am | Am | G | G |
| Am | Am | G | Em F |


REAPER regions .csv the Color represents the sections
Code:
#,Name,Start,End,Length,Color
R1,C,1.1.00,3.1.00,2.0.00,FF80C0
R2,C,3.1.00,4.1.00,1.0.00,1127AE
R3,G,4.1.00,5.1.00,1.0.00,3776EB
R4,C,5.1.00,8.1.00,3.0.00,3776EB
R5,G,8.1.00,9.1.00,1.0.00,3776EB
R6,C,9.1.00,10.1.00,1.0.00,3776EB
R7,C,10.1.00,11.1.00,1.0.00,71BEF1
R8,C,11.1.00,12.1.00,1.0.00,1127AE
R9,G,12.1.00,13.1.00,1.0.00,3776EB
R10,C,13.1.00,16.1.00,3.0.00,3776EB
R11,G,16.1.00,17.1.00,1.0.00,3776EB
R12,C,17.1.00,18.1.00,1.0.00,3776EB
R13,C,18.1.00,19.1.00,1.0.00,71BEF1
R14,Am,19.1.00,20.1.00,1.0.00,0B7427
R15,Am,20.1.00,21.1.00,1.0.00,11AE3B