PostProcessInput2 but BaseColor only

Hi, I’m trying to create a thermal vision effect like Splinter Cell Chaos Theory. I’ve already done the rendering of heat values, but in Chaos Theory they downscale/upscale the render target in order to blur it, much like is done for bloom. I was wondering if it’s possible to achieve this effect, but only for BaseColor. The way my thermal works, is I render heat values to the green channel of a texture (exactly as Ubisoft did in Splinter Cell Chaos Theory), but for me this texture is the BaseColor of the material. I can’t introduce a new rendering pass to the pipeline, so this is my only solution. And there’s no good method to blur this input that I can find.

Thanks, Vaani