Can ASCP suggest the planned orders to purchase primary and substitute item in a fix percentage

We use the ASCP 12.0.

In our BOM, some components have substitute items under it. And our supply chain want to purchase both the primary item and the substitute items in a fixed percentage.

For example, in a finish goods BOM, the component A has one single substitute item B, the used quantity is 1 pcs.

Assume there is no existing supply (no on hand, no PO/PR) for the item A and B, and we have a sales order for the finish goods 1000 pcs. In this situation, ASCP will suggest a 1000pcs planned order for item A. But what we are looking for is two planned orders, item A 700 pcs and Item B 300 pcs.