The CAB2 has the capability to toggle between two engine addresses. This capability is easy to use. Press ENG, key in the address of the first engine. Press ENG, key in the address of the second address.
To toggle between these two engine address, simply press ENG twice.
Example:
Press ENG, key in 3 as the address of the first engine you want to control
Now press ENG, and key in 49 as the address of the second engine you want to control
CAB2 now controlling ENG 49
To toggle back to engine address 3, simply press ENG, then press ENG a second time. The CAB2 is now controlling ENG 3
I have not tried to see if SW, ACC, RTE, and TR have the toggle capability.