OC 1.4.9.3 Drop Shipping Options

We would like to mark some items as drop shippable on other as not.
So if an item has zero quantity but is drop shippable, allow customer to order it.
If an item has zero or customer want more than we have in stock, and not drop shippable, do not allow order.

How would I add this feature or is there a module for this? I couldn't find one.

any update on this? Did you find a mod that would work for what you were looking for? I am looking for the same kind of solution.