i don't believe you can ensure all fish receive the same amount of food. what you can do is feed enough food that all fish can potentially consume within 1-2 minutes uninterrupted. broadcast feedings are probably better for fish to have an opportunity to eat the same or close to the same amount of food.
perhaps feeding a variety of food as well. a combination of flakes, pellets, and frozen. maybe some of your fish prefer pellets of frozen, or flakes over pellets/frozen. feeding a mix can definitely allow more opportunities for your fish to get adequate nutrients.