David,
Shot in the dark.
I was playing around in Item Master and in our current environment we use the Specifications tab to classify each item. Well, our customers do. I am not a user but what I do see is a way you can create attributes for raw items vs the others.

Another thought is to create kits. Maximo Secrets has a good how-to and just by reading it, maybe something to look into.
Kit Items by MaximoSecrets
Again...shot in the dark here.
Adam