ubuntu18.04 How to map a key to a another value but only for specific keyboard

I am using a compact keyboard at home, but a full-size keyboard in the office on the same laptop. When I am using the compact keyboard, to use the arrow keys, I need to hold the Fn key since the default arrow keys are right-alt, ?, Menu and right-ctrl. Any way I can map the arrow keys for the compact keyboard without changing the keys for the full-size keyboard?