The group calendar service is defined in a Class-of-Service definition called standardGroupCalendar:
# # Definition for group calendar service bundle # dn: cn=standardGroupCalendar,<ugldapbasedn> changetype: add objectclass: top objectclass: LDAPsubentry objectclass: extensibleObject objectclass: cosSuperDefinition objectclass: cosClassicDefinition cosTemplateDn: o=calendargroup,o=cosTemplates,<ugldapbasedn> cosSpecifier: inetCos cosAttribute: icsdoublebooking cosAttribute: icsautoaccept daServiceType: calendar group NOTE: When the Delegated Administrator configuration program installs the standardGroupCalendar definition in the directory, the variable <ugldapbasedn>, shown above, is replaced by your root suffix (such as o=usergroup).
The daServiceType attribute defines this as a calendar service for groups.
The calendar service definition also includes calendar attributes such as icsdoublebooking.
However, Delegated Administrator does not provide service-package templates that specify values for these attributes. The Delegated Administrator console provides one service package for groups with calendar service only: the standardGroupCalendar service package. This package does not include calendar attributes.