Event-reminder as a "per-member-group" setting

[Cyboman]

I would like a mechanism for calendar events to remind member groups f.e. 3 days before an event starts.

1. Author creates a new event
2. Permitted members (f.e. moderators or administrators) are allowed to set a "group-reminder"
3. All group members will be notified about an upcoming event, as described above f.e. 3 days before the event begins.

Anybody has an idea if this is possible?