Want to match a property that one data source has to another data source



I currently have two different Data Sources in my Model (D01 & D02). They both share a MID and a CID that can link the data together. I need to be able to look up my data in my D02 Module by a List named Legal Process. I'm having difficulties making this List match the data in my D02. I know I can potentially create a "mapping module" to link the data together with the List, but wanted to know if there is a way to do this in my D02 Module verses doing the mapping module. 


(Let me know what pics you would need to assist) 


Thank you