Cut off ExponentialHeightFog

Hi guys,
I have a question about the ExponentialHeightFog and how to get more control over it.

As you can see I placed a Fog Actor into the scene and everything is foggy as expected, but I want to cut it of at a certain point. Please take a look:

In the floor is a giant ‘hole’ with the black void beneath. I want some fog there, because the player will go some meters into it, but till the end I want pure blackness. What would be a good solution here?

Thanks for your help!