Can you split the keyboard on XW-P1 or XW-G1?

You can define a key range for each of the four zones. For example, you can set up one or two zones to sound on the left side of the keyboard, and the remaining zones to sound on the right side of the keyboard. More information can be found on page E-64 of the XW-P1 manual, or page E-73 of the XW-G1 manual.