Ground clutter with different landscape material instances

A bit of context: I currently have a few different landscape material instances on my map, which vary by component. This includes things like redwoods, snow, swamp, etc; they all have their own material instance to make each paint layer a different texture. So landscape paint layer 2 might do a bunch of different textures depending on the component it’s being painted in. I’m trying to set up ground clutter layer actors for each paint layer in a way that the clutter differs between the different textures in the same layer. I opened up the Ragnarok map and found that they are doing this exact thing and it appears they are using the “Texture Channel” value under the clutter layers section on the GroundClutterLayerActor to do this, but I have been unable to find what these numbers correspond to. Any help would be appreciated!