In theory, you could do this by setting 'absolute times' in timer commands, e.g.:

/timer 16:30 1 1 -Command to start some Download-
/timerDownloadStop 20:00 1 1 -Command to stop all Downloads-

The syntax of the timer command is:
Quote:
/timer[N/name] [-cdeomhipr] [time] <repetitions> <interval> <command>
For further details, check the helpfile for /timer