Kerberos for multiple pc's over shared connection, possible?

[spirites]

I'm currently using winroute, have tried sygate, wingate, nat32, etc. My biggest question is that for college I need to be able to have all my machines behind a nat box/harware router use kerberos. Basically with local ips (192.168.0.x a signal is sent to the authentication server, then the server sends back on a different port (913) and the NAT server has no clue what to do, and the college authentication server thinks it's the NAT box ip that it's talking to. The lynksys router is supposedly good for one person at a time, but leaves everyone else helpless. Port mapping is no good since only one pc will be setup and also everyone on the lan then has access to that person's confidential info unless I also block local access to port 913. Any ideas? Oh yeah, and I inquired of a tech guy that supports Sonicwalls had he never heard of kerberos but *thinks* it will work. Any real knowledgeable people out there? TIA