Blended Cost in Costing Organization

We have two sites, MEX and MON.  They both make the same product, A.  However, item A has different codes in each org - A1 in org MEX and A2 in org MON.  Different item codes are needed as the costs are different.  Item A enjoys high volume in org MEX and consequently, costs there are lower.  Both organizations are standard costed.  However, the COGS on the sales order should be the blended cost (moving average from both orgs).

Without setting up another organization where the costs roll up to, is there a more elegant way to track the blended cost of the product.