Combining Planned Orders from MRP/DRP with unplanned orders in P4310

Good afternoon Support Team,

The only way I can ask my question is by describing my client's current purchasing requirements:

My client requires that when ordering for "special" items, their SO's and PO's be linked together (much like an ST/OT or SD/OD) however, these items are not going direct to customer site rather their Whse so they need to interface with Inventory (D line type can not be used).  Also, the client needs to be able to consolidate various "special" SOs into one PO for each Supplier. The only way I know how to do this is to have the SO's generate Requisition Orders (for linking purposes) and then combine the multiple requisitions into one PO (I'm aware order integrity