After some more testing, multi-master I2C is definitely what I was looking for, thanks a lot Graynomad !
By the way, CAN looks also really nice, I may not use it this time but I'll eventually use it for another project 
After some more testing, multi-master I2C is definitely what I was looking for, thanks a lot Graynomad !
By the way, CAN looks also really nice, I may not use it this time but I'll eventually use it for another project