Any suggestion on this?

I sell shirts with my logo on them.

I purchase the shirts from my vendor, and take them to the embroider.
Then I purchase the embroidery service from the embroiderer.

Then I use assemblies to build the service and the shirt together into my finished shirt that I sell.

This keeps track of my PO's and my COG's nicely.

Only problem I see is re-order?

I assemble, and embroider all the shirts at once.

So for the raw shirt, I almost always have zero in stock.

When I get down to 20 of the finished shirts, I wants to re-order the raw shirts.