With indexAndForward=true on a heavy forwarder, how do we route data to an index with a different name on the target indexer?

Hi Team, We are planning to migrate our existing indexed data to a new Enterprise Server which is up and running, serving other depts. Our plan is to make an existing server as a heavy forwarder which will send data to Enterprise indexer. Before that, for testing and minimizing the outage, we want to enable `indexAndForward=true` so that existing instance and new instance will receive same data and user can still work on the existing system while the new system will be tested. My question: We must change index name on the new system to adhere policy, so how will data routing will work? Say for e.g. on the existing system, data comes in index "abc" and on target there will be another index "def" which should mimic its functionality. Of course we will change the knowledge object to reflect the new index name, but how will data route which comes on index=abc to index=def with indexAndForward=true? Please help!! Thanks Hemendra