Custom query or implementing an association

Hi Folks!

I have an requirement to fetch data from multiple Business Objects (BOs). I am thinking of two approaches, whatever is possible:

1. Create a Custom BO with a Custom query...implement the query to fetch data from both BOs.

2. Extend standard BO1 with an association to BO2. Implement this association to fetch required data from BO2.

Kindly suggest if any of these is feasible or suggest another approach to fetch data from 2 BOs ( they have no standard association between them ).

Thank you!