Automatic Calendar reminders to user group

[optrexnz]

In the notifications, I see you can select email notification of calendar reminder and turn off the ability for a user to be able to change this.
The problem is, it appears as though the user has to select a calendar reminder for each given event. 
I wish to create a members calendar where all events that are created send out a notification reminder that cannot be turned off.

Or failing that, send out a notification when a new event is created in a given calendar.

How do I do this please? 
If it can be restricted to a given group, that would be better.