Comparing BI and BPC cubes

Hi Exerts,

     I have a requirement to create a report in EPM 10 where I have to comare the BW vs BPC so that they can compare the data what has come from BW to BPC, here I have to create a create a local connection to BW , am not sure which one to take among the four local connections. Is there a condition like a common link in both cubes is required to create a report. Thanks

Rk