Determine Components Material

[TimTDP]

I need to evaluate the material components required to manufacture a box.
A box has sides, base, lid & ends and each can be constructed using different materials. I need to determine which components have the same material so that I can optimise the use of that material.
I need to write a function that will return the following:
Lid & base have same material. All other components have different materials
Or
All components have different materials
Or
Lid, base & sides have same material. Ends have different materials
etc

Each component has the field MaterialId

What is the best way to do this?

Thanks in advance