Landscape Material Target Layer

Hey guys,

i created some Substances and I wanted them to paint with Landscape Material in UE4. I watched some tutorials but i always stuck at the point with Target Layers. Im not sure if i´m doing something wrong… actually i hope so
However… everytime I create a new Material with just 4 different diffuse textures and try them to blend with Landscape Layer Blend… it doesnt let me have more then 3 paint layers in my target layer section…



have a great day

Does anyone have an idea ?