There are some automatic backup softwares avaliable, but only Backup Cow has "private cloud storage" architecture so that you can transform your networked computers into a private back up cloud with sync features. You can back up files to network.You can make good use of the hard drive storage in your network to set up a reliable backup system. Don't hesitate to download this automatic back up software for multiple computers, which not only works for local network, but also is an automatic remote backup software.
Please read more details on Backup Cow website: http://www.backupcow.com