Question Blending between different camera materials?

I'm using the Graphics.Blit command to apply a custom shader/material to my camera. I'm adding some depth haze and blur to the background, nothing too fancy.

As the player moves from one area to another I'd like to fade over to a different color of haze etc. Is it possible to fade between one camera material to another using the Graphics.Blit command? Or maybe there is a much better solution to doing this that I'm not aware of? Perhaps I'm going about this the wrong way

I understand the standard post processing stuff might be the answer here but I would love to know if this would be possible using custom shaders/materials.

Thanks!