Connecting Legacy Envrionments to Multiple SAP Non-production Envrionments

I need advice with best practices for managaing testing aganst multiple SAP non-production environemnts. Our parent company is riolling out SAP to all divisions. Our division has the typical Dev & Qa test envirnometns for legacy system interfaced via webMethods Integration Server. Our SAP rollout has a Dev, QA, pre-prod, G1T (hot fix) environments. We interface to SAP via SAP XI (NetWeaver 2004). In our landscape, legacy interfcaes to webMethods and webMethods interfaces (mostly) to XI to SAP.

SAP QA is used for normal project and fix maintenance. Pre-prod for monthly non-regression testing. G1T fro hot production fix tessting. The challenge is managing connecting to the multiple QA type environments with one legacy QA. Have other companies face this challenge and how did they manage them?

Part of the challenge is that the master data and transactional data may be different in the different systems. We also have cross-referencing data between legacy systems and SAP systems such as Supplier Numbers and Customer Numbers that are environment specific.

Below is a diagram of our current setup.

Leagacy QA apps - webMethods QA ______ SAP XI QA

Leagacy QA apps - webMethods QA _______SAP XI Preprod

Leagacy QA apps - webMethods QA _______SAP G1T