Advanced fog in CS?

[Anders-Wisur(Xotic)]

I wonder if it would be possible to add a more advanced fog effect than already in CS, I want to keep the fog we already have, but have an alternative.
If it would be possible to create a fog doing "MULTIPLY" on top of the already textured object, that would create only the bright places affected by fog, and the brighter the more fog you will see, and a black pixel will not be affected at all. that way this is (some kind of) a simplified version of doing rays.

Greetings.