As seen here: https://www.youtube.com/watch?v=1gDJUIrecE8

Pipeline, if, (as I'm 99 percent certain), there is no way to do this, if you can write a script for this I will be eternally grateful!

FWIW, my preferred workflow is to port over to Reaper as soon as possible, so this is not so much for me. However, I'm hoping to to make a handful of "Band-in-a-Box and MIDI" Youtube tutorials when my work/dayjob slows down a bit as it tends to do towards the summer, and I'm guessing most of the folks here would prefer to stay in the BiaB environment.

I will have to give it some thought.
You can use ReaPlugs with MiniHost
ReaStream will send audio/midi to another track in BB RB or another DAW.

ReaJS will run Reaper js scripts in your host.
https://www.reaper.fm/reaplugs/#tour
http://kawa.works/reascripts
https://geraintluff.github.io/jsfx/
http://ajaxsoundstudio.com/cookdspdoc/
https://reapack.com/repos
You can edit the script in BB the second pic is using MegaBaby drum sequencer.
The third pic is https://reapack.com/repos Reaper File > Extensions > Reapack > Browse packages

Full Screen image1

Full Screen image2

Thanks for the response, Pipeline. I had no idea one could run JS scripts in Minihost.

ReacontrolMIDI seems like it actually may do the trick for this purpose.

To touch on a question I posted in an earlier thread, can you use ReacontrolMIDI for switching absolute values as opposed to "ramping," up/down in values automation lane-style?

Tuenis had a great suggestion where you could set minimum and maximum values on an automation lane for switching purposes, but, if I wanted to automate a whole host of VST parameters at various points w/in a single track, I imagine this could get confusing and tedious real quick...

You need to use it in MiniHost so you can chain midi fx because if you load it in the first slot you can only have audio fx after it so you can't send the midi to and instrument, where would we be without MiniHost !!!!
But we do have vst sync now after all my years of nagging.

I have never used ReacontrolMIDI so best to ask in the Reaper forum.