MIDIman Two Keyboard Re-channelling
This preset uses the notes held on one (silent) input and uses them to change the channel of the same note numbers when they are played on the main input:
Here are the notes for the PatchStorage entry
The PatchStorage file is actually two presets (the second is disabled).
Read below and choose which is best for you.
Each uses a Dispatcher to create mappings for the Transforms in the next line.
These mappings are CC#0 on Ch1, 2, 3 .. respectively, So
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the 1st note sets the Note Range for Transform1
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the 2nd note sets the Note Range for Transform2
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etc
When a note played on the main input matches one of these Transforms it is replaced by a Note On on Ch2
Only five notes have been set as Transforms and in Dispatcher just to show the idea. Up to 16 notes are available 
Each Note Off sets the Transform to Note#0 (ie. " do nothing" as this Note#0 is filtered out)
Pipeline 3 ensures each Note Off from MIDI B is sent to both channels to prevent hanging notes.
Versions
in both versions, a few extra pipes have been added to make them easier to rewrite for a different two channels (see pic below):
The second approach uses Transform’s new ability to set the CC# number to the Channel#:
This is version I would choose as I might be using Virtual H elsewhere as part of a more complex patch. (I find keeping mappings in a bunch on one channel helps me not trip up later down the line)
It would be possible to have more, actually!
PS. I tested with the most boring input possible to make the graphics easy to follow. Would be interesting to hear sounds from more creative input from @MIDIman or anyone else…