You don't have to buy 3 copies, you just need to add the Networking Option ($500). This is a one-time charge.
They don't use the "cloud" or a cloud-based drive -- they communicate directly with each other to stay in sync in real time (so it's the same result as using a cloud service, but your data is only on your computers). If they are on different wifi routers then you would likely need to set it up as "Networking through the Internet" -- see here:
http://campgroundmaster.com/help/net...heinterne.html
Stan Spielbusch
[Forum Administrator]