Domain Script

This is going to sound like a dumb question or an extremely simple one

I'm trying to use script to determine what domain a remote machine is a member of.

Something like

If <remote machine IP here> = <domain1> then
join local machine to <domain1>
Elseif <remote machine IP here> = <domain2> then
join local machine to <domain2>
else join local machine to <domain3>

This script is going to run on a freshly imaged machine.
It has to determine what domain the domain controller at this site is a member off then join the machine to that domain.

The reason it has to do this is that this same image and script will be used across several different domains and I'm trying to make the script figure out what domain to join by itself so I don't have to customize it for each site it is run at

any ideas?

I was a little vauge I think. The only part I need help with is the part with determing what domain the remote machine is a member of. I know how to make it join a domain and how to use the conditionals and all that stuff

Thanks