Hey,
it is possible to combine multiple calendars into one.
Example: Calendar of Person1 and Person2 should be combined in one.
But so that you can see which entry is from which person.
You can achieve this by use of the sharing function. When shared the user who can see both calendars can choose a color-theme for each individually.
Also works with caldav on mobile devices (personaly tested for iOS 10)
The sharing with users approach that Hollerauer suggests is nice, but insufficient. I would like to have 4 calendars combined into a single URL for external embedding, and I can’t find a way to do that if I cannot create a single combined calendar. Maybe there’s a trick, but I have not found it.
No that’s not how it works. Every user has at least one personal calendar. But you can of course share a calendar with induvidual users or with a group of users, and then embbed that calendar externally. You must then of course tell the relevant users that they have to use that specific calendar, for appointments that should appear on that external resource.
EDIT:
Or maybe you could use a web based CalDAV client on that external resource that connects to the induvidual calendars, and combines them into one view. Just like a mobile or desktop client would do it.