How to write-off multiple transaction (invoices)?

We have invoices that we want to forgive and not collect on.  They were entered on a specific G/L date and hit the G/L on that date when the transactions were processed.  How do we forgive or  write-off a group of transactions (of a specific Type and/or GL Date).  This process needs to write-off the amount owed and make the adjustment on the G/L so we know not to expect the revenue.  Future audits dictate our need for a precise and well-documented method.

Thank You.