Thanks guys !
@StringsNwood : For the master/instanced material, I will take a look on it with your videos link.
@Hirk : I had tried to bake ID color and then play with mask ID in SP, but, my color texture baked was not efficient, I don’t know why.
I guess I have to try again 
On another forum, where I also post my question, someone give me a way : Atlas texture + vertex painting on UE4. I think with this solution I should achieve Something correct !