Multiple shaders

[Side note: my search for this topic returned 30 similar ideas, but only listed 10. When I clicked on the "20 more..." link, it took me to the top level for feature requests]

I would like to apply multiple shaders to the same shape layer. For example, I want to use a circle to mask a portion of the scree. I use the Segment Between and set to opacity to 100% for the portion of the circle I want to use to cover something up. In addition, it would be nice if I could also apply a gradient shader to give a 3D look.