Code:
on ^*:quit:{
  var %chan = #test
  if ($nick !ison %chan) { return }

  var %addr = ( $+ $address $+ ), %msg = ( $+ $1- $+ )

  var %i = 1, %n = $comchan($nick,0)
  while (%i <= %n) {
    if ($comchan($nick,%i) != %chan) {
      echo -i2tc quit $v1 * $nick($v1,$nick).pnick %addr Quit %msg
    }
    else {
      ;echo -i2tc quit $v1 * custom message line
    }
    inc %i
  }
  haltdef
}