Hi Juan,
You can have just one transport target as client for a business system in SLD. I don't think you will be able to do this via SLD and transports.
The question now is how to make it work:
You can create a business system BS_SAP_QA_220 without an issue.
Below link should help you with approach:
http://scn.sap.com/thread/3374220
Hope it helps!
Ambrish
