DAViCal is a server for calendar sharing. It is an implementation of the CalDAV protocol which is designed for storing calendaring resources (in iCalendar format) on a remote shared server.
CalDAV/CardDAV path: /caldav.php/user/ (e.g. https://your.server/davical/caldav.php/user/)
Contact group method: groups are separate VCards
Configure well-known URLs so that you don't have to enter the whole path (recommended).