how to blend two or more materials?

thanks but this example mixes two textures not two different materials.
With Vray or Octane I have a mix-blend node.
For example I can mix a glass with a marble
With UE4 we need a lot of masks to blend materials because the material editor handles them one by one.
That’s why I see a lot of nodes in many examples…

If the material node have the rgba output we could mix several materials.