[SHELVED] Material Layering Feedback for 4.19

Hard to phrase what my request ist.
We have SetMaterialAttributes and GetMaterial Attributes. We can select single Material Inputs (BaseColor, Metallic ,Specular etc) from these.
Is there a possibility to have these Selections as a Parameter for LayerBlends? It would make LayerBlends more flexible, since we can Blend multiple Material Inputs together.