For simple mapping of keyboard ranges, each rack supports a keyboard split range and transpose setting.
In Cantabile Performer, these settings can both be controlled through sub-sessions allowing each rack to have different settings for each sub-session.

Keyboard ranges and transpose settings are both defined by playing key ranges and transpose intervals.

Also, these settings are smart enough so that if you change transpose while a note is held, the matching note off event will be transposed by the old amount, saving stuck notes.