As far as all the queens hatching together? No, all the eggs selected to become queens aren't selected in a row, on the same frame. I have made some splits in swarm prevention, only to have the colony swarm anyway. Upon inspection, I found the remnants of a queen cell way out on an outside frame where the queen doesn't very often visit. At least I didn't think she did. As far as the "decision" to save multiple queens, I have no idea if it's an accident, a plan, or the genetics of some hives. We can keep bees because they do certain things MOST of the time, and we can manage them within those boundrys. When they act outside those boundries, all we can do is react.