Anything like Javascript eval() function

Hello,

I'm trying to parse JSON coming in from an Iterator but the name of the JSON element could change names.  For instance, different custom field names.

Much like the eval() function in Javascript, I want Fusion to be able to read a name dynamically.

I've attached some screenshots to help me desribe the exact scenario.

I have the name of a Role in the 1st_Module and I'm looking up a Custom field with that same Role Name.

That does return JSON data, which I'm trying to parse in the 2nd_Module.
However, the Role Name will change with different assigned Tasks.
Is there a way to dynamically set up the 2nd_Module to accomplish this.  You can see from the 2nd_Module.png file what I've tried, but doesn't work. 
At time of the scenario running, Fusion errors with not valid JSON.  I'm trying to type in a string that points to the JSON element.  So I need Fusion to eval() the string.

I hope that makes sense of what I'm trying to accomplish.
Thanks for any ideas,
Kelly