Overwrite Inventory on Product sold

Hi!

I need some help with the following topic:

One of my customers needs a woocommerce shop for his local photo store. He owns two physical stores with 2 different inventories. Over the last couple of days I found out that this isn’t very easy to handle using woocommerce. So I bought 2 plugins which might help solving this problem:

1. ATUM Multi-Inventory(https://www.stockmanagementlabs.com/addons/atum-multi-inventory/) gives me the ability to set up multiple inventories for each product; problem is, the inventories are reduced chronologically(until the first inventory is empty, the next one won’t be altered)

2. Local Pickup Plus(https://woocommerce.com/products/local-pickup-plus/) gives the customer the ability to select at which store he wants to pickup his order; problem here is, there is only one inventory supported.

I now want to combine those two plugins and set up my own inventory logic, depending on where the customer wants to pick up his order. Do you have any idea how to unlink the standard inventory handling on order complete and then use my own inventory logic? Would a self made plugin make more sense then overwriting everything in functions.php?

Thank you very much in advance, I would be very thankful if someone here could help me.

Kind Regards,

Philip Steyrer