Change keyboard mapping ONLY for Bluetooth Keyboard

I have a Bluetooth “Camera Shutter” dongle. It emulates a Bluetooth keyboard. I’ve paired successfully, but I want to change how the buttons behave.

Currently, they’re mapped to 123 (Volume Up) and 36 (Enter).

I’d like to change their mappings – but only for this Bluetooth keyboard. I want my laptop’s keyboard to be unaffected.

My end goal is to have a Python program run when one of the keys is pressed.

Some things I found which didn’t work:

I want to press “Volume Up” on my external keyboard and have a command run – without interfering with my internal keyboard’s “Volume Up” key.

Any ideas? Ubuntu 14.04.4 LTS. Thanks.