Hi Michel,
We made a video to be posted to YouTube about this. We just need to tweak it a bit before posting.
In the mean time, make a new zone, tell it the scanner number is something you don't have (like Scanner 9) and then go to "Also To" and add two or three zones. You will notice that there is this area to the right where you can indicate that only a part of the incoming zone is used. Enable that, and adjust that (separately for each zone you said "Also To").
If you mess around with it a bit, I am sure you can get it working.
Bill