Configure 2 XML feeds, merge 2 XML feeds into 1 (for woocommerce WP ALL Import)

Issue: We have 2 major suppliers, their feeds need to be connected to WP ALL Admin to update stock levels and price. The problem, when 2 feeds are connected separately, stock levels from one supplier (for example: 30) are overwriten with stock levels of other supplier (for example: 0) as both provide similar items with same SKUs. Technical task: 1) XML feeds need to be configured according to show all products from two suppliers (documentation from suppliers provided, gateways access will be given at the start of the task) 2) XML feeds need to be merged in one (manually, or using Yahoo Pipes), showing average price + VAT + fixed price and total quantity from 2 suppliers. Only challenge, that both suppliers have different variables (e.g. SKY can be marked as SKU, other have itemcode marked as SKU in their xml feed). 3) XML feed needs to be fully compatible to use with woocommerce extension of WP ALL Import plugin for the following fields: SKU, price, quantity.