Easier said than done....
Those keybeds are HW only and do not have an encoder.
I don't know...but you would have to be sure the physical aspect AND the electronics would work perfectly or you have a butcher job.

My solution...(maybe :-)...get a T4 and slap a MIDI controller under it. Use the MIDI keybed for everything (easy MIDI setup) and use the T4 keybed for RH3, or whatever.

You can use a Fatar or whatever you wish as the MIDI keybed. All it is is a MIDI message machine. Many types are available these days for pretty low cost and could be 61, 76, or 88.

If you spend som time with the physical setup you can have the lower exactly like a organ...overlapping keys and all.

The only issue it causes me is the darn music stand...my eyes are gtting older (as well as other parts of me) and I would need to get that music stand closer somehow...actually I saw on YPKO that someone did that. Aso, I can get some 'music reading' glasses!