You can access JMS message information using XPath expressions that navigate the service message object (SMO).
If you invoke a mediation module by sending a JMS message to an export with a JMS binding, you can access and update the JMS message using mediation primitives. Most mediation primitives let you navigate messages using XPath expressions. If you implement your own custom mediation primitive, you can access message information from Java™ code.
/body
/headers/JMSHeader/JMSMessageID
/headers/properties[name='JMSXGroupID']
/headers/properties[name='MyProperty']