Hi all,
My understanding is the same as the responses to date with respect to current functionality. Just wanted to add as a note for future possibilities that there was a good discussion on this topic at the Technical Committee meetings last month (June, 2014). The discussion confirmed that many companies have this or similar use cases that result in the desire to Owner-associate a single CAD model to multiple WTParts. Our own use cases at Cummins include the material variation you described, as well as a number of other Part level differences that impact cost or durability, but not physical geometry. Based on the feedback in the TC meeting, the prospects seemed quite good that PTC will continue to look into allowing multiple Owner associations to a single CAD model in the future. I would highly recommend sending a message to the host of that session, Jennifer Pierron from PTC (she participates in the PTC Community as well), to add the feedback on your use cases to her existing list.