Hi,
The simple solution is to unparent the child you don't want to rotate, rotate the parent and then re attached the child.
If this is not possible ( for example, if the child need to move but not rotate), then, either you move the child to follow the parent, else, you apply a counter rotation to the child at the same time as you rotate the parent. So if you rotate by 10 degree on the x axis, rotate the child by -10 degree on the x Axis using the parent as reference.
Try the first and second solution, if you need a counter rotation, you'll need a custom action to expose rotateAround within playmaker. If you can't write the custom action yourself, le me know, and I'll do it.
Bye,
Jean