Virtual Characteristic: Can it be added to a Multi

I have Multi based on top of three cubes:

Cost Centers/Internal Orders: Actuals

Cost Centers/Internal Orders: Commitments

CCA IO Planning Cube

My task is to have PO Descriptions in front of Internal Orders in a report. Note, the first cube mentioned above gets data from two ODS's (Cost Centers Actuals and Internal Orders Actuals).

I'm thinking of implementing a Virtual Char so I can get PO Descriptions in front of Internal Order, but i need to completely understand the linkage between the two.

Please give ideas, you will, of course, be rewarded.

Thanks in advance

Fran