How to change stock with a feed from actual shop

-- HikaShop version -- : latest
-- Joomla version -- : latest
-- PHP version -- : ?
-- Browser(s) name and version -- : all

Hello we have a real shop with a system that keeps track of how much products we sell. When we sell something this automatic lowers the amount we have in stock. So when we check our system we know what we need to order extra etc.

Now do we want to connect this to hikashop. Is there someway we can automatic link this feed to the stock in hikashop?

So when we sell for example 10 products A in the real shop from the 100 we had. When we donwload this feed at the end of the day and insert it in hikashop its lowering the stock from this product to 90.