Multi-Pass Rendering

[goro]

Render Node is a node; so my assumption was, we can apply shader to Render Node. Please correct me if I am wrong. We haven't applied InvShader to quad1, because we were planning to apply some other shader to quad1. So our process was:
Render Scene2 on Render node --> Apply InvShader on Render node and use it as a texture on quad1 --> apply SomeShader to quad1.

As per our knowledge vizfx.postprocess can be applied to window. We don't know how to apply it on scenes. Please let us know if there is any way.

Thanks!