why are my ical invites sent to everyone on my network instead of just to those I want to invite?

Hello everyone!

I'm upfronted with the following issue using iCal. We have small buisness with 10 clients all running Lion. Our server is a MacPro with SL. Every single user has its own CalDAV Account within iCal and on the server. Using iCal upbrings the following issue.

When someone is creating a new event and inserts just certain atendees from our local office, this event is somtimes also shown within iCal on clients that weren't invited within the event itself.

This is pretty awkward, as obviously not all events are ment to be seen by everyone in our network. Strangely this issue only applies to some of the clients within our network. If you're wondering, every client-pc is used by just one person with its own unique login.

I have been searching the internet all over but unfortunately haven't found anything. Another point is that this issue startet as we upgraded our clients from SL to lion about a year ago.

This is what we're trying to achieve with iCal:

every clients/user has it'S own CalDAV-Account synced with the server. Each user has several calendars all synced via server. Some calendars don't belong to any user, but are instead calendars shared by everyone (for e.g. for days-off)

Now when a user creates an event within in iCal on his client and invites some attendees this invite should only be sent to those persons invited by the creator of the event. For everyone else this event should not be visible.

Furthermore we have only one meetingroom. If the creator of the afore mentioned event wants to use this room for his event, this room should be displayed as occupied for the time of event. This sometimes isn't shown as somebody else wants to create an event using that room at the same time (this might be a total different issue I guess...)

Anyone having a solution that might help?

Here's the following I have tried so far:

checking the server configuration for iCal -> found nothing that could help me or at least reveal a hint to where the problem lies

checking all client's iCal and CalDAV settings -> again, found nothing that could help me.

Maybe even though I have tried checking some settings as mentioned above, it could be possible that I have overlooked something..

Regards out front for helping me solve this issue and hoping to hear from the community,

Moritz

btw, this is not our/my only issue with iCal...;-) So look out for further threads to come.