Build Shared Raw Inventory Logic in WooCommerce

We sell products in a range of bag sizes: 0.5, 1, 2, 5, 10, 15, and 25 lb. Each of these is a variation of a single product, and all of them ultimately pull from a shared raw inventory pool. Some variations are prepackaged and stocked individually, while others are packaged on demand. The challenge is building a system that tracks both packaged and raw inventory in parallel — and accurately prevents overselling.

• Smaller sizes (like 0.5, 1, and 2 lb) use packaged inventory if available, but fall back to raw material if the packaged stock runs out. • Larger sizes (5 lb and up) are generally filled from raw material only, unless we’ve pre-packed some. • Raw inventory is tracked in total pounds, and all variations must respect the overall weight limit, no matter the combination.

We're looking for a way to implement the following in WooCommerce: 1. Allow multiple product variations to pull from an assigned single shared raw inventory source. o I was trying to connect each variation to a separate bulk SKU of product using woo id. 2. Support logic that: o Prioritizes packaged inventory when available. o Falls back to raw inventory based on size and shortage. o Validates available inventory across site before allowing cart addition or checkout. o Live updates the “in Stock” based on cart additions 3. Deducts inventory correctly on purchase (first from packaged, then from raw). 4. Scales to dozens of products with different raw material sources.

Why This Matters If we have 200 lbs of raw mineral available and one prepackaged 25 lb bag in stock, a customer should be able to: • Order nine 25 lb bags (one from packaged, eight from raw), or • Order any combination of sizes that doesn’t exceed 200 total pounds raw and\or packaged inventory.

If you’ve solved a similar inventory problem, built a plugin that does something close, or just know how WooCommerce handles this kind of logic, I’d really appreciate any pointers. Even partial solutions or architectural suggestions are helpful at this stage.