product kit

Hi all
i am new of this forum.
A little question: is possible to modify parameter construction of product kit (virtual product) by dividing in two different element the Increase/Decrease stock on parent change?
Is interesting to have the possibility to select if the parent product can only increase or only decrease or both increase and decrease when the virtual product is buy or sell.
Anyone have think to this possibility? can anyone tell me if this change is already under study?
thanks in advance for information. Sorry for my bad english expression