The Record Producer
Page 21
Chapter 2.
Selecting
Passing Rule #2:

Passing from one part to that same part consecutively is not
passing. (Duh!) You will need multiple parts to pass the ball
effectively. If your song only has two parts that are worthy of holding
the ball, then you will only be able to pass the ball: (part one to part
two and part two to part one)

Passing Rule #3:

Parts and instruments are not the same thing! A useful trick is to
separate single instruments onto multiple tracks. This will give you
the ability to create multiple parts with the same instrument.