The only thing I can think of is having a separate tank, where you are raising live mysis, connected to the main tank with an inverted u-tube connecting the two tanks. Large enough for the shrimp to swim to the horses, but small enough that the horses can't go through.
It sounds good at least... lol
If you can't find the time to feed seahorses, maybe seahorses aren't the best idea.
125 malawi cichlid, 110 Discus, 75 reef, 30 reef, 27 reef, 4 planted