Members who are permitted to add group calendar events can add events from outside calendars (such as Google Calendar and Microsoft Outlook) to the group’s calendar:

1. In the outside calendar application, create an event (or appointment or meeting) as you normally would.
2. In that event, add the group’s email address (typically in the form groupname@groups.io) as a guest or attendee.
3. Send the outside calendar event invitation.

Group members receive the event invitation by email, and the event also is automatically added to the group’s calendar. 

Example: You create an event in Google Calendar and add the Groups.io group as a guest. This action generates an email message that is sent to the group with a calendar invitation. Assuming you have permission to add group calendar events, Groups.io creates an event in the group’s calendar in addition to sending the calendar invitation email to the group members.