Let's say I have to buy 2 barrels of crude oil and 1 tonne of iron every month to operate my business. I want to hedge myself against rises of the prices of these commodities (perhaps more for crude oil if I believe iron will be more stable than the oil).My question is: Is there any benefit of treating this as a 2-dimensional pricing and hedging problem, as opposed to just treating each commodity separately? (I'm of course assuming there is some correlation between the commodities, otherwise there is clearly no difference.) Will it cost me less to hedge if I go 2-dimensional? If this is the case, what is an intuitive explanation for the lower cost?