Automatically combine duplicate part numbers on the same line (after warning)

If we bill out a duplicate part number on the same line we should get a warning saying "Duplicate part number. Do you want these parts will be combined?" or something like that. If this prevents the "duplicate part number" messages from appearing that would be great. When adding from SPORD it doesn't let you change quantity. So you have to delete both lines, transfer to inventory and then re-add. Which is a pain.