Yeah, you need to return to the event and return from there:
Code:
on ^*:Text:*:#:*: {
  if ($notify($nick)) return
  alias1 $1-
  if (%shouldreturn) return
  halt
}

alias1 {
eventual code..
if (shouldreturn) { set -u %shouldreturn | return }
eventual code..
}
Instead of a /stop command, maybe /halt could be improved with a switch so that /haltdef is not executed when /halt is used

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