Issue with Jump Target

Hello Friends,

I created two querys and i am doing RRI between these two querrys. Can you please help me with the below scenario:

How should i handle this scenrio:

Sender Data: The data has some blank values in sender-feild1.

"If sender-feild1 is not blank, assign sender-field1 else sender-field2 to the receiver-field1"

Where to write this logic in RRI Assignments?

So, Please help me with this issue.

- Ganga