apply discounts to several/all line items on sales orders

I know that I can apply a discount on sales orders two ways: 1) per line item -- which reduces that sales amount directly (my company prefers this method) and 2) on the separate line item at the bottom of the invoice, which puts it into a separate GL account.  However, I would like to have the discount applied to every line item on the sales order without having to manually do this on each line...is there a "apply discount to all line items" type of function?