Thanks Bitt, now this is where I guess proprietary solutions win, 1 widely installed app vs 3 separate ones that I'll never find decent support for (one of the reasons we're moving away from Scalix). I'll look into Cyrus, but the address book and calendar are integral to what we do, and the ability to set permissions on shared calendars and address books relatively straightforwardly is invaluable.

How visible would a setup like this be to the user, i.e. would all the functionality be available within a single client app (and what would that be)?