How to plan an item with specific lot management requirements

We have various products that are lot controlled.  For example, an item has 3 lots in inventory.  Lot A = 50 pieces, Lot B= 25 pieces, Lot C = 60 pieces.  There is a demendent demand for this item for 100.  ASCP sees that there are 135 on hand so does not plan an order.  Our problem is that the dependent demand requires that all 100 come from the same lot.  In this case none of the lots is for 100 so we need to make more.  Similarly, we have 2 demendent demands for 60 each.  One of the demands