Cannot use both height texture and colored splat map in terrain material

I am creating a material for terrain. Each layer is set to Height Blend. I am using a Layer Blend node. Inputting the base textures into Layers slots and inputing the RGB channels of the splat map into corresponding Heights. This gives me the ability to have terrain textures that match my splat. However, I can’t figure out how I would also use greyscale heightmaps to also blend using height.