How to Group Calendars in Mountain Lion
In the Calendars app in OS X Mountain Lion, you can organize calendars in groups that contain more than one calendar. To create a new calendar group in Calendar, follow these steps:
Choose File→New Calendar Group, or press Command+Shift+N.
A new calendar group named Group is created and added to the On My Mac section of the calendar list.
Give the new group a name by selecting Group and typing a new name.
To add calendars to the group, create a new calendar while the group is selected, or drag existing calendars below the group name in the list.
When you release the mouse button, the Personal calendar moves below the Family + Personal group. Note that the Personal calendar is indented and the Family + Personal group has a disclosure triangle to its left.
Now you can show or hide all calendars in the group by selecting or deselecting a single check box. You can still show or hide individual calendars by selecting or deselecting their check boxes, of course.
Here’s how you might deploy this feature. You could create individual calendars for each member of your family and put all the individual family calendars in a group called Family. Then you could make all the family-member calendars visible or invisible with a single click of the group calendar’s check box.
If you have an iCloud account, you can publish your calendars and invite others to subscribe to them by choosing Calendar→Publish. The others receive an e-mail inviting them to subscribe to your calendar. That way, you can all see at a glance who’s doing what and when they’re doing it.