Kraig, I feel your pain: been there.

First, IMO BoM is a wrong model for this one: in BoM you can have the same element on several different levels. For example, you may use the 8 #13 bolts to assemble an automatic transmission, then you use another 8 of the same bolts to mate the transmission to the engine, and finally use 10 bolts to attach the assembly to the frame of the car.

This is not your case, I believe. Please correct me if I am wrong.

I would use CLR Integration and the power of XML LINQ to handle this, in a few lines of C# code. Not every SQLS installation allows that; if yours does, being in your shoes, I would go for it.

I can whip that code up for you. It might cost you a drink.