HCI - How to use multiple parameters (with XML loads) in a groovy script

Step1: Stored XML (data) in an external parameter (EXP1).

Step2: Working on another xml feed from Successfactors - used a groovy script to manipulate data on second xml. Can someone guide me in reading the external parameter EXP1 in my groovy script in step 2.

PS: I don't want to combine both the xmls using content modifier.