minilogin is ip based the only way to run more then one client from the same ip is to change the ip of the non active accounts before you zone the active character this must be done each and every time before you zone a character the correlating accounts ip has to be set to the correct ip and the non active (non zoning) Accounts must be changed to 0.0.0.0 for instance.
I am working on a system to make this process easier based on an example i saw on the forums not too long ago ill post the binaries when ive gotten it working untill then all i can suggest is using the minilogin php login script from the following post
http://eqemulator.net/forums/showthread.php?t=22846