Overall discount to be applied on the Header level rather than value getting updated for each line

Summary:

Overall discount to be applied on the Header level rather than value getting updated for each line

Content (please ensure you mask any confidential information):

Currently the Oracle discount will deduct each line. The client wants to deduct the supplier discount as an overall value rather than same getting applied to each line. Is there any means to capture the same without propagating the discount to each lines?

The user wants the line price to remain the same and apply the discount to the overall ordered amount without it moving down to the PO line level where it affects the PO line level unit price.