Post processing stack V2 problem. 'Depth only' clear flags not working.

Hi there

Basically, my problem is that I'm trying to create an effect where a few select objects in the scene glow red, while the rest do not. In the old post-processing stack, I could just create 2 cameras, set one to only render the selected objects and hey presto, it works, but in the new stack I have a problem. When I apply an effect to a camera with 'depth only' ticked in the Clear Flags setting, the effect applies across the entire scene irrespective of what the camera is instructed to render. Any ideas how to fix this?