Only server versions
The owner of the calendar (user who created custom calendar) can copy it with all it's settings and assign a new owner for the copy.
Enter the Edit menu of your custom calendar and press Copy:
Then select a user to whom copy of your calendar will be applied and press Copy again:
After that in that user's calendar list new calendar appears with all it's settings, layouts, filters and so on.
The user is now the owner of the copy and can make any changes. Changes made in copy don't affect source calendar.