PBCS - approach to new classification of data

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We are on PBCS, here is the new requirement

We have a SPARSE dimension called Product hierarchy, which has part numbers(more than 90,000) as leaf level and have product lines as intermediate parents.
Now client wants to classify this product lines further into a new categorization lets call it "CODE" and this new CODE will have the same leaf level members as the part numbers,but WITHOUT modifying the PRODUCT hierarchy. So that the data dump for Budget scenario can be classified according to the new 'CODE' as well apart from existing dimensions.
Any suggestions on the approach to implement this?