Yes,
you can set the doorbells to have two different rings, and you just
need to pair transmitters to receivers for a new code one by one,
following below steps:
1. Pick the sound you want on one of receivers.
2. Press and hold the volume button on this receiver about 5
seconds, the receiver will blink with a "ding" sound and then
immediately push one of the transmitters to pair with the receiver.
Finally you will hear the music you set.
3. The operation method is the same to pair other transmitter to receivers.