Sorry I wasn't sure what you were asking from my last post. An SSS essentially creates a black and white shape, with an optional fall off to black at it's edges. There is a displacement tab which uses that B&W information to displace. Now if you want to use an SSS (I'm not sure this is the correct acronym as it generally means Sub Surface Scattering in other 3D apps), feed the B&W shape into the blending input of a surface layer. This means what ever happens in the surface layer, it will only work in the area defined by white from the SS. That includes surface colour and child attributes etc. If you want to layer several SSs, like in your last image, without them influencing each other (atm, you are layering one after the other, so one colour overlays another), you will need to add and subtract these shapes to create your intended areas of influence. Which is what this thread is about. This is why it's generally a good idea to use the blending input on a Surface Layer, because this will then act as a stencil for your effect, on the main input.