I understand that an option to add sub-categories in the inventory module may be in the works (which I am psyched about!). What would be fantastic, is if we were able to flag low stock levels for a sub-category instead of at the item level. For example, as the owner of a tech shop, I need to know only if we are low on 240GB Solid State Drives in general. I don't So, I don't necessarily care about a specific drive being low on stock, only that we are low on 240GB SSD's or low on 64GB Flash Drives, etc.