One Portal System to Multiple R/3 Backend via ITS

Hello;

Current environment as follows;

EP6.0 SP16, R/3 4.7 on WAS 6.20 (Not Netweaver), ITS 6.20.

We are using ESS and MSS functionality via Portal==>ITS==>R/3.

For the development, QA, and training R/3 systems, we would like to use to one Portal system. Of course a second portal system for the production landscape. My questions are;

1. Can we connect multiple R/3 systems to one portal for running ESS and MSS?

2. Do we need dedicated ITS systems for each R/3 system or can the ITS be shared?

thanks in anticipation of your responses

Ragoobir