File to IDOC and Proxy - Multiple Interface

Hi,

I need to build a File to IDOC and File to Proxy based on the content of the file.

I will receive a file name called PlantPP.csv. Based on the plant either I need to route it to IDOC interface or Proxy interface,

Here the problem is I will not be able to use Receiver determination since in both the cases the receiver is ECC. Since it is linked with Business system, I will not be able to create multiple service as well.

How do I tackle this? 

For eg., Plant 3000 should go and create an idoc whereas plant 4000 should create a proxy.

Good thing is one file will contain only one plant at a time, so I dont need to worry about checking line by line.

Regards

Krish