Extended receiver determination

Hi,

Synchronous Scenario:-

source system request customer information - PI ihas to do JDBC lookup and find out customer information is residing in which system and give back the response back to source system.

We have two receiver system and it is synchronous call - DB table has 40 millions customer information and lookup will return either it resides in Rx 1 or Rx2.

Approach:-

1. As this is synch scenario hence Extended receiver determination will not work as SAP Rex Determination structure is async.

2. BPM is out of question as we have to lookup 40 million customers with JDBC lookup.

Any other approach or suggestion?

chirag