Интернет-решение для Совместного использования
Просто создайте некоторые псевдонимы в своей qmail конфигурации. См. http://lifewithqmail.org/lwq.html#aliases о том, как сделать это.
It seems like the easiest solution is to set up a VPN that will connect the netbooks back to the office. Configure the VPN client to automatically connect and -- ideally -- the employees won't have to worry about whether they are physically at the office or working somewhere else. From their perspective, everything should Just Work. This obviously requires a little configuration and testing on your part, but it's a pretty common solution to exactly the problem you've described.
There are a variety of VPN solutions out there. OpenVPN is a nice cross-platform solution (I'm using it under OS X, Linux, and Android right now), but I don't have any experience with the Windows client. Cisco obviously sells products in this space, and there are a variety of other options out there.