We are considering a change of email servers and Kerio Connect is attractive. However, I am concerned about calendaring functionality. I found an old forum post that states the question well:
"We want to create a single public calendar that everyone can see - using Windows XP/Outlook 2003/KOC 6.4.1. We want a way for people to put an entry in their own personal calendar and some how mark it so the entry auto add's or syncs with the public one. If an entry is private it wouldn't sync to the shared public calendar...
Has anyone ever heard of a way to do this - in any way with any software?"
This is a high priority feature, so if Kerio cannot do this, we may consider Exchange. Does Exchange provide functionality like that described?
I don't know of any product that provides such a specific feature, and I've used Kerio in the past. I've not used Exchange, but there are some security questions that the proposal raises in my mind, so I'm suspicious that you would find someone that supports that.
If you are sufficiently interested, you may consider finding a tool that is sufficiently open, and essentially writing a tool to do this. The functionality sounds simple enough.
To summarize, you could create a calendar for everyone called PublicSync (or whatever, just make it consistent for coding simplicity) and regularly update the public calendar with the combination of all of the PublicSync calendars.
Alternatively, users could all share their PublicSync calendars with everyone, and Outlook can effectively combine them (I think it has a UI to show a bunch of calendars effectively merged; I could be wrong). You could do that with Kerio OR Exchange OR any Outlook integrating calendar product.