Step functions has pre-defined parallel states, but have you come up with a solution for dynamic parallel states?

Such as: a parent state's output will determine the size of the input to pass on to multiple copies of identical parallel state children (the number of which is determined by the parent's output). These get the same input or a specific slice of the same input from their parent.

I guess these could be created dynamically within the parent, then deleted afterwards. Not as clean as declaring this in the states markup though.