Request: Parent - Child Logic to affect quantities

I may be using "Parent-Child" wrong in ZZ, but in Planswift, if I list an item as a "child" of something, and then I double the quantity of the "parent",

the program is smart enough to double the "children" along with it. Could something like this be added, or if it exists elsewhere, have this feature be extended to

this specific thing I am asking about?

Thank you,