Just an untested idea.

Code:
on *:QUIT:dis_en $nick .enable
on *:PART:#channelname:dis_en $nick .enable
on *:KICK:#channelname:dis_en $knick .enable
on *:JOIN:#channelname:dis_en $nick .disable

alias dis_en {
  if ($readini(dis_en.ini,Nicks,$1)) $2 #group
}

menu nicklist {
  Dis_En Able
  $iif($readini(dis_en.ini,Nicks,$$1),Remove,Add) $$1:{ $iif($readini(dis_en.ini,Nicks,$$1),remini,writeini) dis_en.ini Nicks $$1 $true }
  -
}