Using multi-select for variable list of parts

Hello!

You have equipment (ex, car) with 20 parts (ex, tires, brakes, etc.)

Many parts can use the same material (ex, rubber, steel, etc.) , so the user should be able to select the applicable material(s) vice typing the same thing over and over for each part.

This is the clunky way I have it working so far, but there has to be something more elegant:

1. In an Excel List (Data>List), type in the info for the first part.
2. Click the Material List button (multi-select box) to choose the materials (2 in this case) and add those to an unused cell (A2).
3. The first list item (the first part) uses the A2 value for its Material column.
4. So far so good.
5. Add a second part. It needs 3 materials.

How do I update the 2nd part's row with the 3 materials?

Same for the 10th, 18th, or 100th part.

??

V/R Lost