Hi Ron ,
Thanks for your post.
From my point of view, what you want can be achieved with our Product Levels premium addon.
With this addon, you can set BOM product parts (S Variations) and link them to distinct final product variations, so when one is sold, the stock of the other linked variations will be accordingly deducted.
You can read more about the Product Levels addons and how it works in our knowledge base.
Best Regards,
José Andrés