It's very complicated although someone here might know an easier way to implement it.
For me, and my limited knowledge from my rF1 mod, you have to edit the 3D models files so they are separate pieces and then make them detachable parts and edit the files in the damage.ini. I looked into it for some parts but it is only achievable if you have a good knowledge of 3D modelling and the rF1/rF2 file structure.