Randomize hiding mesh from mask in material

Hi, i’m new with UE.
so i’m modding Foxhole using UE 4.24.3 and since i can’t recreate & access the blueprint, it seems that my only option is through material.

so what i want to do is to create 3 variant in 1 mesh and show only 1 variant using channel packed mask that i created for each variant.
is there a way to do that? i tried Per Instance Random but not working.
thanks in advance