Get them on a schedule!! That is the only way I survived with my triplets. They should be eating every 3 hours, immediately following their nap. Let them play for a while after they eat, then put them down for a nap and the cycle starts all over. Sleep, eat, play, etc.
Also, four months is too early to be giving them cereal in formula. If you are trying to bulk up their calories, get some Human Milk Fortifier form your doctor to add to your breastmilk, (if you are nursing). The idea that adding cereal will help them sleep longer is an old wives tale.
A book that was a great resource for me was "On Becoming Babywise". One of the authors even has triplets, and there is a whole section on taking care of multiples and getting them on the same schedule, or a similar schedule depending on your situation.
Feel free to send me an e-mail with any questions, or if you just need to let off some steam. I've been there and know how being sleep deprived, delirious and overwhelmed feels!!