PCG content filtered by material?

Is there a way to make PCG content which is limited to a specific material. I have a world which uses static meshes for the landscape and it would be nice if there’s a way to get PCG to populate it, but only for specific materials.

The terrain does this already for “grass” objects – you can paint (and output) a “amount of grass” channel.
It doesn’t look like PCG can read this channel currently, and with the move to Nanite instead of Landscape, maybe that’s not on the radar – but can you live with the kind of procedural generation that “terrain grass” implements?

The issue is that PCG only seems to work with landscapes. If you have a terrain made from static meshes, then PCG doesn’t seem to be usable. I’ve also noticed that PCG does not get along with some nanite meshes. Still scratching my head over that one.