Intranet geolocalization

Hello,
Is it possible to use @IP subnet go geolocalize user ?
In my entrprise network, each entities have a subnet for example:
163.100.100.0 - 163.100.100.255 => site 1
163.100.101.0 - 163.100.101.255 => site 2

So can i create a files with subnet and town or contry for geolocalize each site ?

I uses Xampp 1.6.6a (apache 2 php 5.2.5 mysq)
Piwik 0.4.2
Geoip plugin

thank’s

You’d have to either edit the GeoIP database, or hack the GeoIP plugin to use your scheme.