There are probably a few ways to do this, but I what I did was to schedule the power circuit to my auto feeder to turn off for most of the day, and only turn on about 5 minutes before the feeding time. Then I set the pumps I want to turn off to be dependent on the auto feeder device being powered on (Off if On). Then about 15 minutes after the feeder 'cycle' command, I set the power to the feeder to drop which re-enables the pump(s).
Hope this helps.