Hey Rikki :
I hope you are doing well. 
Connecting 2 keyboards and using them together - combined with external interfaces - for recording in a DAW e.g. is not so simple ( at least for me ). I have still to learn a lot. 
Last week I added a new Korg Kross2 synth to my Tyros4.
A synth is a completely new challenge for me but apparently I am very motivated. 
I wonder if this new setup will ever work in XGW ... I really doubt it ... making a Korg synth voice list for me will not be easy, I am afraid.
I guess XGW might be over for me. 
I am experiencing questions I cannot answer due to lack of sufficient knowledge ... I tell myself learning keeps me young. 
I am very lucky and grateful members of this Forum are always there to help me out and to support me.
Take care.
Best wishes, Jeff
Hi Jeff, unfortunately been many years since I used a Daw for songs, and then it was only for editing midi files.
I only use xgworks for style editing my so a voice list is not necessary for me, the bank and program changes are embedded in the file.
Personally if it was me , I’d be recording my backing track style in my sx900. Loading it into xgworks. Then just record the additional Korg melody tracks into xgworks. Personally I wouldn’t try and replace Yamaha sounds with Korg sounds in style parts, or just keep recording your Yamaha songs as you are already and just record the additional Korg tracks.
You can add program and bank changes manually, but a voice list would be better. Someone I think did a video clip on how to do it, but still a long process.
Xgworks has multiple midi inputs/outputs, but your midi interface needs to have a couple of midi outs so that both keyboard can play their parts
The only time I’d hook the keyboards up via midi would be if you wanted to play melody voices on Korg instead of on tyros in real-time.
Learning new stuff does keep the mind active.