Connecting multiple SAP Systems

Hey all

I know that we can connect multiple systems with enterprise portal. But my situation is like this that I have SAP ECC 6.0 as well as SAP R3 4.6 C. ECC system is just for testing purpose so i need to connect with it ESS and MSS Business Packages for my developers to test various functions in the newer SAP Version. Along with that I also need to connect EP with SAP R/3 system which is live and being used by our end users. They also need to perform activities in the same 2 packages i.e. ESS and MSS.

So my question is can i connect few of my users with ECC and others with R/3 4.6C. on the same Enterprise Portal on the same 2 business packages (ESS/MSS)

Regards

-Bilal Nazir