Hello,
Not for the moment, that feature still isn't our priority for the moment as we have a lot of feature on our TODO list that are waiting and because that feature will require a heavy development in Hikashop but also in components that are integrated with it.
A solution can maybe be to add a another 100 quantity for your product, and then customize your product page views code so that it will display the product quantity minus 100, so your customers will be able to order product that are "virtually out of stock".