[CalendarServer-users] Access to all calendars

Hi, I have a calendarserver running on Ubuntu Intrepid. For authentication I use kerberos. For the moment I'm using the accout.xml to add my users. The final installation should use the NSS-dir-service. My Problem is, that I have access to all calendars I may write to personal user calendars and to group-calendars. I needn't belog to the group What do I do wrong? Georg