Hii YR,
You can modify the Production Data Structure, so automatically whatever the resource assigned corresponding, Production Version automatically will change to secondary .
Example: Two PV attached assigned with routing and every routing has different resource. You can modify the PDS, to primary or secondary, which will change the resource priority to primary and secondary as well.
Use the BADI : CUSLNTRTO_ADDIN for Change Production Data Structure.
Regards
Debashis