You can use $me to always be your own nick. The method that differs as little as possible from your method would be where %ip contains mainy addresses
but you must /set the %ip variable elsewhere then have the event be like:

elsewhere: /set %ip *!*@203.212.27.190 *!*@123.123.12.123 *!*@321.321.32.321
Code
ON *:JOIN:#: {
  if ($istok(%ip,$address($nick,2),32)) {
  /msg  $me <message-test>
  var %a $findtok(%ip,$address($nick,2),1,32)
  set -s %ip $deltok(%ip,%a,32)
  }
}

You can remove the -s if you don't need to see how many IP remain in the list