How to apply sound mixer only to particular class?

Hello,

When I make a sound mixer I can add classes, but it seems this is only for some extra effects. I actually t hought this was the list of all the classes that this sound mixer would be applied to. But sadly this is not the case, the sound mixer is always applied to all classes which is totally not what I want. I want to apply a specific sound mixer only to one specific sound class.

How can I do this?

Here is why I need this:

I have a couple of weapon sound that need to be EQ’d when a player is underwater. Then I also have a mixer that EQ’s a handful of special sounds when a player is inside a cabin / roof overhead, however when this mixer is active the weapon sound may NOT be EQ’d. Now I know you can set “apply effects” in the sound class, but this is not a solution as when I set the apply effects to false on the weapon sounds they will no longer be EQ’d when underwater.

It almost looks as this is a limitation of the engine which would seem extremely strange to me as this is a VERY basic thing that should simply work out of the box. o_O