Pixhawk additional external sensors

Hi there!
I have an Arduino Uno currently and I’d like to use I2C to connect to the Pixhawk and give it some more AHRS data in addition to what it’s already got. I’ve got an Arduino Portenta which is capable of CAN and I want to use that in DroneCAN later to send the same data over with more diagnostics, taking full advantage of the DroneCAN protocol.
As a start, how would I go about doing this on the Pixhawk end?
I can send over the Arduino Code if neccessary, just wanted to see if it was possible to begin with
Thanks!

Take a look on this post and all the possibilities that it brings: