First of all, we need to understand that pocket aces and kings are not the type of hands we want to play in multiway. The ideal situation is to go heads-up on the flop. Thus, don't limp from early position with AA and KK, it's a dangerous tactic and you should avoid it. After all, if you limp in, there are likely to be several other opponents on the flop with you, which means that you will have to bury your hand if you encounter significant action (unless you hit a set yourself, of course).