a timed solution sending one line each second would be e.g.
Code:
; syntax: allunban #somechan

alias allunban {
  var %b.num = $ibl($1,0), %l.nr = 1, %b.nr = 1
  while (%b.num > 0) {
    var %do = $iif((%b.num > $modespl),$modespl,%b.num), %b.string
    while ($numtok(%b.string,32) < %do) { var %b.string = $addtok(%b.string,$ibl($1,%b.nr),32) | inc %b.nr }
    .timer 1 %l.nr mode $1 $+(-,$str(b,%do)) %b.string
    inc %l.nr | dec %b.num %do
  }
}