debian fully automatic install
What you want is the "preseed" functionality of Debian installer.
http://wiki.debian.org/DebianInstaller/Preseed
Basically, you create a configuration file with all installer questions answered, use that file to compile a special kernel and boot it (or you can create a CD ISO image). Details in the Debian wiki (link above).
You'll have to create different preseed configuration files to differentiate between installations, I'm not familiar with a way to differentiate based on MAC address of network device.