We recently switched our email service and I'm now in the process of depreciating old servers and firewall port. I've closed a port and am seeing loads of block logs flooding things because most users still have their iCal CalDAV accounts point to the old server.

Is there a way (without know the account title, but knowing the server address and that it's a caldav account) remove the old account through a shell command or any other easily deployable policy method?