If I understand your question . . .
You are looking for items where curqty = 0 within a system. However, an item could be in more than one pocket. This seems a reasonable interpretation of "I need a list of itemid's where they are not anywhere in the parent "system" (given they still might be in pockets in other systems.".
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.