The same way the Sforzando is playing back the realtracks and realdrums changing instantly from one chord section to another, the BBBPlugin Standalone could work.
So whatever Style you choose it will load those instruments and change to sections of the source files to fit the chord being played same way the pic/video below is doing, it's changing from one source file to another.


Watch: https://www.dropbox.com/s/gk1xggd2z8n2oqx/Sforzando-Drums-Guitar.mp4?dl=0



If you are enthusiastic to help out you can try these:
Right Click Save Link/Target As

Guitar, 12-String Acoustic, Strumming Ev 120 - ram wma.sfz
CountryEven8_120_Style - ram wma.sfz

Copy the sfz into:
bb\RealTracks\Guitar, 12-String Acoustic, Strumming Ev 120
and
bb\Drums\CountryEven8

then drag the sfz into Sforzando and press the keys.
You should get instant playing of RealDrums and RealTracks from different files and sections.

These are for Win wma, if you have a Mac just drop the sfz into a text editor and change all the .wma to .m4a then save.