User based calendar and group based
Thanks so much for reaching out!
You can assign a user to be an Organizer of the event by adding them in under Events < Organizers or add them directly in the Edit Event page.
You can create a category, rather than a group, and assign an event to that particular category.
If you have any other questions about The Events Calendar, please post in our WordPress.org forum so that we can assist you over there.