Hiding a part of the circuit? If that's what you mean, yes; you can use a black simple shape (uncheck the edge color to be sure) between the warp shader and the mask input of the surface layer. Or a (color=black) surface shader just there (with the warp shader output going to the surface shader's input), the black surface shader masked by a white simple shape, or any other masking method (PF, painted, image map).
Would that be working for you?