Stock level count automation form another board

Hi,

We have our products listed on a board (as items), with their associated stock level in the next column. Essentially a stock list/inventory.

On another board we log our product requests. Under each product request, we create a sub-item where we can log each requested product (from a dropdown) in its own column in the subitem. These columns are already linked to the stock list board.

Is there an automation I can setup that will automatically change the stock level in the stock list board, every time I add a product to a column in the subitem?

As an example, let’s say we have 10 x Item “A” in stock. A customer requests item “A” from our stock list. We add item “A” to the first column in the subitem under the request in the requests board. The automation, then changes the quantity in the Stock List board from 10 to 9.

Essentially, every time a stock list item is selected or assigned in the subitem columns under a request, the stock list quantity automatically reduces.

It’s important for us to be able manually increase the stock level figure in the stock list board (when new stock arrives), while the automation essentially subtracts from it based in the amount of times that item is selected within the subitems of the request board.

Is this possible? How would I go about it? Any help is much appreciated.