Modifier that uses the list price

I have a situation where if a specific customer places an order for any item, a new item is added to the order.  I've setup a Promotional modifier type.   However, in the modifier setup, Advanced Pricing forces me to manually enter a new price for the Get Item modifier line.   I do not want to do this.  Instead, I want the module to pull the item price from the referenced price list.  I'd hate to have the business users updating the Modifier each time the Get Item's price changes.  They should be able to utilize the existing list price or