Sync products reduce inventory first from Product 1 and then from product 2

[smartleben]

Hello, I need to sync the stock from product A with product B and product C. Product A needs to be the sum of stock from product B and C. When a order is made for product A I need to reduce inventory first from product B and when it reaches 0, the next orders reduce inventory from product C. Is there an app that can help me with this? Thanks!