I want to set a global 'default' restriction on Team Calendars so that clients (who sit in a user group called "clients") cannot see (or edit) any calendars unless they are explicitly granted viewing (or editing) permissions.
Example: All calendars have restrict viewing from 'clients' user group. // I then select a specific calendar, grant 'view' access to a specific user by user name.
Please help! 
Thanks, 