Neverwinter Nights - LAN play with invalid CD keys?

[Rumik]

Hey there,

I'm trying to play NWN with my friends on a LAN. I'm the only one with a valid CD Key. My friends can get past the Login bit simply by disconnecting themselves from the Internet temporarily, however when they come to log into my server their CD keys are rejected. Does anyone know how we can plaay on a LAN with 2 invalid keys?

Thanks.