Dual output key map assignment

[phcuriel]

Hi, thanks for this cool program.

I wanted to see if I could use a custom key map to mimic a 31 button accordion on the computer keyboard. The trick is that with diatonic accordions the same key produces a different sound while the bellow is pushed and another sound on the same key when the bellow is pulled. Would it be possible to assign a key as a modifier, lets say the “Tab” key to mimic “bellow action” so that if that key in pressed it will send a different midi output? I the case of the diatonic accordion if I use the “z” on the keyboard to output “C#1” note but it I press the “Tab + z” keys output a “B” note? The modifier key should also intercede if other keys are pressed simultaneously to output their secondary output. Let say If I was also pressing the “x” key which would normally output “F” note to output a “G” note if the “Tab key is pressed”. So if I have both keys “z” and “x” and sending a primary output, it I press “Tab” they both switch to sending a secondary output.

https://github.com/flit/MidiKeys/wiki/Creating-Custom-Keymap
I read the wiki on how to do custom key map and I was able to do the mapping for keys to mimic the layout of a “Diatonic Accordion in F B bE” to the computer keyboard. Now I want to add the alternate output to mimic bellow action. Is there an example of syntax I should use on the Plist file to do this? Does this capability exits? Thanks