I'm having an issue with my rocket breaking apart. I have the top two stages as inline tanks and engines, but my last two stages used for the brunt force of early launch are 6 tanks and engines radially around the core tank. I have only in line decouplers, no radial ones. I noticed that at some times during a launch, if conditions are right, the engines start to flail around and it gets worse as time goes on until it causes the rocket to brake apart. it would appear that the first tank 3rd stage is where the radial attachment is and nowhere else along the whole length of the 3rd and 4th stages. Is there a way to tighten this down? Some component I haven't unlocked yet or a command in the construction interface I'm not aware of? If you need any more information or screenshot so the rocket or the problem occurring, I can capture those for you. Thank you for your assistance, Sarik