Revise google spreadsheet script -- 2

Script used in google spreadsheet to parse gmail messages needs to have one update to it to include an additional case of parsing words. That case looks at the origination of an email address and when it is a "mail delivery system" email, or "Undeliverable" email or an emal originating from postmaster, parses the email message to find the underlying email recipient from which the email was sent from. That email id is then put into a spreadsheet. Looking for someone with experience in google spreadsheet scripting to take this on. Very simple script and addition to script. Again, it is a few lines of code added to an already existing script.