Ideas for visualizing process flow with converging nodes?

I'm looking for an effective visualization for the following (greatly) simplified data set.  In this example there are two items, Label and Envelope.  The Label is made up of individual components paper, artwork, and adhesive while the Envelope is made up of paper and adhesive.  The components are made from the individual raw materials shown.  Note that the Label and Envelope share the same adhesive material.  Finally, the raw materials are related to their respective material category.

Any ideas?  The Sankey diagram is close, but doesn't seem to handle converging nodes.  Maybe there are some other visualizations I should be considering.