Bill Only line to close with a delivery

 We have situation where we want to add a bill only line (with a non-shippable part number) to a sales order along with several inventory items.  All of the items are to ship together so we use a Ship Set to manage this.  We want the Bill Only line to invoice with all the other lines, not immediately when the order is booked.

Is there any way to set up the Bill Only item so it will wait until the shipment is made then close and invoice with the other lines?