Hello, thankyou for trying to help me with this, and I apologise if I wasn't clear in what I was trying to do. I have the V4 Bot from DAZ and I wanted to create groups, from which I would create a material, the purpose of this was to apply a glow / ambient light effect. I hope this is making sense. The first time I tried this, I selected the polygons and created a material for them. This ran into trouble when I realised I had selected additional polygons accidentally. I tried to remove these polygons by deleting them in the group editor and reassigning the material with the same name I had used before, but this didn't work. I could see no way to delete the material, so as to start again, in the group editor or Material Room. This is when I asked for help.

I tried the method you described, but when I opened the file, I didn't get anything like you did, please see attached file. I am currently working with the helmet and mask, which are both props.