If there are several email recipients, all recipients can be invited to a new appointment.
How to invite all email recipients to an appointment:
Select an E-Mail.
Click the More actions iconin the detail view.
Select Invite to appointment from the menu.
Complete the data for Creating an appointment.
Also see
Sharing Email Messages
Subscribing to Email folders
Saving all email recipients as a distribution list
Parent topic: E-Mail messages within a team