Auto complete rule for termination classic UI

Hi Team,

I have one requirement. Suppose I have added one DFF field in Work relationship page as Column and stored value as "ABC". When I want to terminate any employee, under termination action I select a value as "ABC". Once the value got selected under term action, then it should check for column value "ABC". If both value matches then it should throw error. It is possible to do in Work relationship Classic UI? Below is the condition it should look like:

If Term_action = "ABC" Then

(

If Column(DFF) = "ABC" Then

( error message throw)

)