Shared Inventory Tracking Across Variations

On items that have multiple quantity variations (example: ball sales at a pack of 1, 2, or 3), it would be really helpful from a inventory tracking standpoint if you could assign a quantity of inventory tracking to each of these items. 

Currently the tracking works on an all or nothing basis, so if I have a variation pack of 2 balls that I sell it will only remove 1 item from stock instead of 2. This causes a lot of manual override on inventory count. It would be really helpful if you could select this option to remove 2 items from inventory. Essentially having a shared inventory tracking among the variations that sell different quantities to keep inventory count accurate.