I hope someone with experience in pairs trios, etc. can answer this for you. This is going o be a major concern of mine when I bond Boon and Phenom, provided Boon makes a recovery from a lengthy bout of stasis (he has a genetic disease that makes him prone to this).
That being said, some things I have conjured up about this is feeding all three of them separately. Make a feeding time for each of them, and allow each one 15-20 min with their pellet ration while the other two watch. When bun 1 is done, put him back with the others, and get bun 2 and give him his ration and alotted time to eat his pellets. When he is done (or time is up) then put him back with the others, and get the third bun and give him his rations.
If it were me, I would let the cute little black and white pudge go first to kind of get the other bunnies watching and thinking, "hey, i wanna eat too!" so when you put him back, he'll have had his fill, and the other two will get their turn.
Then, put them all back in their pen/living area and give them unlimited hays and whatever veggies you give.
If you do three pellet feedings a day, you'll have to sit aside time to do this, but if you do twice pellet feedings a day, this might be easier if your schedule is tight.
That is just what I may do...it may or may not work out for me..or you.... hope someone else with better advice can come along.