If you want 'sharability' in your data filters then your best approach is to implement as database tables and affect the row filtering via joins.  Depending on how you implement data filtering you can have it part of the metadata in the RPD -- but if you do it this way; then they other reporting system will have to connect to BI server (via odbc) and pass in logical SQL (similarly as the Presentation Server does).  This way does work, but you need to develop the logical queries before hand (which defeats a lot of efficiency).