Dear Mr. misterbob,
I know that advertising is not acceptable and actually this why we never advertise on this forum out of our respect but actually our service is specifically created to solve the issues you mentioned.
It can provide you an online central calendar on our server that all of you can access and modify. Marking your event as private can only allow those you choose to see it. Marking an event as public makes it available for all people.
I'll keep it short and urge you to check this link out:
http://insynch.websupplier.net/download.html
And please download
Merak Groupware user's manual and read more about the available calendering options.
Hope this can help.