Sales BOM quantity variance

Hi Everyone,

Below are the requirements from my client:

Sales BOM maintained in the system as follows:

If you order 1 PC of Mat A, then 1 PC of Mat B (a label) will be added in the sales order.However, if you order 1 Box of Mat A (which is 8 PC), you get 8 PC of Mat B (8 Labels) which they don't want.

Requirement: For 1 BOX of Mat A there should be only 1 PC of Mat B (i.e. 1 Label) because you never attach 8 labels to 1 box.

Is there any way to handle this in standard SAP?

Thank you.