Using the graph API you can create a new Group Event /groups/{id}/events/{id} however because it's in a group, you're unable to set the Organizer of the event because it will always be the group it's self.

This leaves the only 2 people that can change the 'meeting options' (via a link in the calendar appointment)
- Organizer - This is the group itself (the group doesn't have a login - so it's not an option)
- The Owner - The account who run the API call to create the event. If this is a service account, then this isn't an option.

When creating an event, or updating one, we should be able to set who is a presenter or attendee of the event.