Multiple Materials For One Object C4D Problem

Hello ! I've some c4d minecraft models and every single model uses 3 materials by using polygon selection and I'm trying to import it to unity but only 1 material is imported and I can't make every polygon a mesh because I'm using randomly generating position and I can't group them into a null object because I need a mesh renderer , filter and coliider for this object so how can I solve this problem ??!