Yes, but it does complicate things a little. For example, the organ sound engine needs to be on in order for the drawbars to send midi however, I can connect the YC MIDI In block to IK B3-3 and map all the drawbars to it without any issue. GP lets me redirect the YC keyboard/controllers and connect them to my VST. So, yes… the YC sound engines are ‘on’ but in this configuration they’re never actually triggered.
That said, I tend not to do this with my rig. It’s much easier for me to use the KeyLab controllers exclusively to manage my VSTs… much of it has to do with muscle memory.
You might find this interesting too (popped up yesterday). https://youtu.be/wdkKL-9cTOU?si=Ylxi2TmmVLtyuRWZ
Note that the YC actually has three Hammond organ types and I think H2 is grittier and my preference (not the H1 used in the vid) Mastering YC: The Organ Section - Yamaha Synth