If it were possible, I’d expect that the manual would tell you how to do it.
However, you could use an outboard Bluetooth transmitter for the secondary zones. The Avantree Oasis seems to be better than average.
However, depending on the distances in question, you may have issues with Bluetooth. If so, it will require a pro-audio wireless transmitter / receiver solution, which will raise the price of admission considerably.
Regards,
Wayne A. Pflughaupt