Huge landscape: how to hide vegetation/foliage when building lights?

I’m currently working on a huge landscape, and at the moment it’s using real time lighting.
(see the attached picture)

There are a lots of foliage/trees etc in the scene. These were placed using the foliage tool (static lighting disabled)

Now I want to build the lighting (to get good renderings of the houses and the town you partially see in the picture), but I want to build everything EXCEPT the foliage.
Is there a way to “hide” it when building? Or add the foliage to a “light-building exception” list?
I know that I can simply delete all the foliage, build the whole scene lights, and then put it again…but if there’s an easier solution I’ll take it :slight_smile: