How to trigger Dataloads on specific Applicationserver on Sourcesystem?

Hello,

we are loading data via Processchain form our ECC6.0-Sourcesystem to SAP BW.
The Soursystem contains three applicationservers.
Applicationserver2 is because of the number of batch-processes the favorite for the dataload.

Now my question...
how can i achieve that the dataload from BW always starts the extractionjobs on applicationserver2?

Any ideas are welcome...

Thanks and Regards,         
Oliver