API or Transparent?

I have 3 XBee 900HP/S3B Pro and was wondering if I should use transparent, API, or both modes. I require the routers to send sensor data back to the coordinator and the coordinator must be able to identify which router the data came from. Also, the router would be linked up to an Arduino most likely.

Use API.
Transmit Request frame takes 64-bit MAC address as parameter. The Response will contain 64-bit MAC for matching request to reply purposes.