How can I set up the form so that more than one recipient can edit the submission?

It's either you will set up multiple recipients in the form email, then add the edit link in the email template.

For multiple recipients: https://www.jotform.com/help/39-Send-Notifications-to-Multiple-Recipients.

To add the edit link: https://www.jotform.com/help/40-How-to-Let-Users-Update-Their-Form-Submissions-at-a-Later-Date.

Or, share your form as a sub-user account: https://www.jotform.com/help/232-How-to-Share-Forms-with-a-Sub-Account-User.