How to isolate a multi vendor deployment environment in JBoss EAP 5

Issue

• What are your suggestions for Class loading policy for a multi vendor deployment environment such that:
  1) We need to achieve maximum re-usability of application specific jars and no duplication of jars, that is, all our applications should be able to make use of jars, preferably from common point.

2) We need to make sure that our jar files don't affect our vendor applications. So again these should be specific to our applications alone.

3) We need to make sure that our framework jar files don't create problem with the versions deployed by our vendors.