Need Sleep

I'm not sure how they do it, but somehow my twins, Allison and Katelyn, are able to notify each other when they are falling a sleep so they can make sure to take turns.  Katelyn will fall asleep, while Allison is wide awake. As a start getting Allison to fall asleep Katelyn wakes up. This literally happens within minutes...sometimes seconds. Sometimes as I'm laying Allison down, Katelyn will pop her eyes open. I can't figure out how to get them to slepp at the same time.

My two year old is on a very dependable sleep routine, but it took us 18 months to get her there. I feel out numbered now.