Allow us to set rules so that we can use different stock when a certain product is ordered

So we currently have a number of products (example SKU SSRUSKIN6.0M) which are also used to fulfill orders with different sku's (example SKU SSFINGERPRINT6.0M).

It's basically the same product but they have different skus because one is for customers who want a wedding ring with a fingerprint engraved on it and the other is for those who just want a plain wedding ring, so we have them set up as different products with different sku's so we can keep track of it all.

We would like to set them up on mintsoft so that when an order containing example SKU SSFINGERPRINT6.0M is placed, it takes the stock out of example SKU SSRUSKIN6.0M instead of us having to keep replenishing the stock levels for the SSFINGERPRINT6.0M SKU.