Vendor stock control by simple form

-- HikaShop version -- : 2.3.2
-- HikaMarket version -- : 1.4.3
-- Joomla version -- : 3.3.3

Hello,
I'm setting up a multi vendor site and have a question about stock control by vendors. Because Vendors in the online shop also have a normal shop it's a challange to keep the stock data up to date. Now vendors should login, search for the product en decrease the stock with one sold item manual. Same thing if the recieve now stock in the store but then increase the stock levels online.

I also have a licence of RSformpro that have the possibility of some costum scripting. So the question isif it's possible to do it by a form after a vendor log in like:
____
Productcode [FIELD] (vendor fills in or scans the code)
Vendor id [ID] (get vendor id or name from Hikamarkt database after login)
Stock level change with [Amount, standard value by Rsform -1]

Submit
____
Then system checks if vender has such a product:

if not: returns "no product find in online store"
if found: decrease level with amount requested in form and return text "Stock changing succesful"

Hope I can get any help on that.
Thanks