Hi Jim,
You have to configure SSO between your GRC and Portal system. Then in portal create an iview and then assign that iview to a role(like how you assign a t-code to a role). Deactivate password for all your approver user id's in GRC System. Copy the portal URL and paste it in the email body of your notification template(for approver copy the approver Work Inbox URL).
Regards,
Neeraj