I have a production BOM where I have the same component listed three times.

1. amount of "goop" that is needed to fill the containers for the finished good

2. amount of "extra goop" that is needed to prime the tooling

3. the same "extra goop" to be a by-product as it can be reworked and used in the next batch

I do not want to have component #2 and #3 to be used to value the production BOM.  

How can this be done ?