Orders for On-hold Customers in Pick and Pack

Question

If a Customer is placed on hold after an order is loaded, then the order appears to flow through the pick and pack process until you attempt to add the Delivery, when you are prevented.
Is there any way to prevent orders for Customer who are on-hold from appearing within Pick and Pack Manager?  We are wasting time picking orders and getting to the despatch stage only to find out that the Customer is on hold so we can't despatch the goods.

Answer 1

Thanks Gordon, I finally found the time to follow your advice.
In case it is at all useful to anyone else the change I made to Transaction Notification was as follows
IF     @transaction_Type IN (N'A',N'U')
AND     @object_type = 156
  BEGIN
     IF EXISTS (
          SELECT          T1.AbsEntry
          FROM          OPKL T1
          INNER JOIN     PKL1 T2
               ON     T1.AbsEntry = T2.AbsEntry
          INNER JOIN     ORDR T3
               ON     T2.OrderEntry = T3.DocEntry
          INNER JOIN     OCRD T4
               ON     T3.CardCode = T4.CardCode
          WHERE          T1.AbsEntry = @list_of_cols_val_tab_del
               AND     T4.frozenFor = 'Y'
       BEGIN
          DECLARE          @DocEntry int
          SELECT          TOP 1 @DocEntry = T3.DocEntry
          FROM          OPKL T1
          INNER JOIN     PKL1 T2
               ON     T1.AbsEntry = T2.AbsEntry
          INNER JOIN     ORDR T3
               ON     T2.OrderEntry = T3.DocEntry
          INNER JOIN     OCRD T4
               ON     T3.CardCode = T4.CardCode
          WHERE          T1.AbsEntry = @list_of_cols_val_tab_del
               AND     T4.frozenFor = 'Y'
          SELECT          @error = 156,
                    @error_message = 'Customer is on hold for order ' + CAST(@DocEntry AS varchar(10)) + ' - picklist cannot be progressed (SP_TransactionNotification)'
       END
  END