It's hard to explain, but I will try my best.
I have sub-assy "A" with two components. One (component X) is fixed (fully defined) another(Component Y) is under defined. Position of Part Y in Sub-Assy A will know only when you add Sub-Assy A to the Main Assy B. That means one componet of B mate with Y on A and fully defined the position of Y. Y is fully defined in Assy -B but when I open Sub-A, I can move Y anywhere. It wont be problem if I wouldn't have to create Drawing of Sub-A. Because position of Y on drawing should be based up on Assy-B but drawing is of Sub-A.
I already used solve as flexible option to perform all steps I explained.