Passing Key Value WEBI

I have 2 separate columns in one table in DB returning 'Key' and 'Value'

I want to show 'Value' field as prompt and based on what value is selected I want to pass corresponding key to back end in WEBI

How do I achieve that?

I am ok even changing DB table design as well.

Using - UDT, BI4.1SP6 WEBI and its a universe build on ORACLE DB