Well, you can setup a while loop to loop through all the users, I dont know what you do with that info, but heres an example of making a token set with every user and there idle time in the "nick=idletime,nick2=idletime" format.

alias idlechan {
var %x 1
while (%x <= $nick($1,0)) {
var %idle $addtok(%idle,$+($nick($1,%x),=,$nick($1,%x).idle),44)
inc %x
}
return %idle
}

Use: $idlechan(#channel)