alias noticeveryone {
set %numNicks $nick(#channel,0)
set %x 0
while (%x != %numNicks) {
set %x %x + 1
notice $nick(#channel, %x) this is where your msg goes
}
}

that would be how to do each one individually but if you do that in a huge channel you will flood yourself and/or the server so its probably not wise to do....
anyway...why would you want to do it individually instead of noticing the whole chan???