Now that sounds like my two little girls (6 and 4). Sally has a voice that would strip paint from the walls (if only it were true, maybe her Dad would get around to the painting ...), and Elen, the older one, pretends she has no idea how the destruction occurs. I'm so tired of Elen's picking fights with Sally (and then complaining that Sally is screaming) that I told Sally she could hit Elen!
It's the opposite of the pair of boys ... I told Billy he could hit Tom, since Tom always starts everything. Only now Tom is heavier than Billy, so it's a good thing they're not in a fist-fighting phase at this point!
Since Bobby is 7 years older than Joey, I also told Joey he could hit his brother. Bobby is an instigator, too. He needles Joey until he either gets furious and throws things at Bobby or bursts into tears only to be told what a "baby" he is.
I have threatened to crack their heads together more than once. At least they have learned to take off their eyeglasses before they start wrestling.