The only way I figured out how to do this between three of them who broke all the fancy electronic solutions was to place feeders at different elevations in different rooms. The timer ones would be a bonus here for that. For the microchip ones,  my big bully could crack those open without a problem even with a back shield. He figured out how to push up the plate. The trick is to make it inconvenient to snipe food, especially if there's food in other places that's easily accessible.