Well today they could use VPN and wireless networking, but it wouldn't work anyway. At some point somebody takes the laptop and walks out of range thus getting the data not synchronized if you want that. One way would be to create a script that'd synchronize the data when the user logs in or out, and tell people to log out before they leave the network that's holding the servers and log in when they get back..or just create a nice clickable icon on the desktop that syncs the directories.
If you happen to find out how to know when the user is about to leave (when the synchronization would need to happen), tell me too
another solution, of course, is that every time a file gets edited or created it gets synced with the server, but that sounds like consuming a lot of time and resources..