Shareaza

Is there a way to halt uploads of a) a specific file or b) all files that allows active uploads and queued uploaders to complete their downloading, instead of interrupting them, but prevents further queueing for the file(s) at issue until it is undone or Shareaza is restarted? (It should presumably respond with a busy signal or other non-permanent not-now status, and not generate new query hits for those files, while in this state. If this is preparatory to deleting a file or desharing it, the file would go from "busy" to "404" when actually removed. More usually it would be preparatory to a restart, modem reboot, or other interruption after which the same files would remain available though.)