Smooth blending of post process depth fog

Hey there. I’m working on a marshland location of an open-world game. I needed to add some localised fog, as the exponential height and atmospheric fogs are seemingly global. So I went the post processing route.

I got the material looking quite nice and it works perfectly apart from blending it. I use several post process volumes in the map, and the rest of the map is not meant to be nearly as foggy as this area, but whenever I blend between the unbound global post process volume and the one in marshlands with the depth fog, the fog intensity jumps up.

In other words, if the blending weight of the fog post process material is between 0 and 1, the opacity of the fog is much higher than if the blending weight was at 1.

Is there a way to fix that through materials or is there perhaps a different way to blend the volumes? Or perhaps there’s an entirely different way to have relatively cheap, localised fog?