Dome light Alpha? -> Multible domes with Full Light select

[Ihno]

Hi, I'm testing the LightSelect in full mode and I try to use multiple domelights.
I have a HDRSphere from a studio situation and made masks to separate the lights.
So I have 6 domelights, 5 for every light and one for the room itself.
It works pretty well but the reflection and specular is not working.
Only the first seems to add reflections.
I think the different dome lights kind of overlay each other. So my question is: is there a way mask the domelights with an alpha channel?
Or make them transparent by the brightness of the image so that black would be fully transparent? So the domes would be added on top of each other.

I can make them not affect the reflection and put the unmasked hdri in the reflec/spec environment but that's only a workaround since I wouldn't have them separate anymore...

[Ihno]

After no one answers, I assume its impossible currently.

What about a general interest in an additive mode for domelight's?
I think it would be a great addition. As we'd be able to change the intensity of, lets say a cloud in post.