Is the Swiss Transfer Ticket good for travelling from Zurich Airport to Grindelwald and then return from Zermatt to Geneva Airport say 10 days later?
Yes, you can absolutely use it like that. All details can be found here: myswissalps.com/ swisstransferticket. You can purchase the ticket through www.swissrailways.com/ en and print it at home if you select "Online Ticket" when asked for delivery preferences.
Enjoy your trip!