fulfilling single "large size" item order with multiple "small size" items

[sammers]

My store sells paints that can be ordered in different sizes (eg, 10 ounces, 20 ounces, 50 ounces).

Is it possible to fulfill a customer order of a larger size (eg, a single 50-ounce) with several smaller sizes (two 20-ounces and one 10-ounce) on the back end? In a way that maintains SKU and inventory tracking? The main goal is to automatically fill larger size orders with multiple smaller ones when the larger sizes are out of stock.