If you are using P5, you can apply the same material to all groups withing a single object in the materials room. After setting up a single part with the relevant material, right-click on the background and hit "select all". Thenm r-click again and hit "apply to all". If you have many objects to apply the material to, save the material in the library, then step through the objects, applying that material in the same way (I don't know of a faster way of doing that bit - I'd be interested in finding out if there is one). Cheers, Diolma