SQS on Relate and edit/display field other than name

I am currently on SugarCRM 6.5.15 Professional.

A Relate field stores the id of the related record and by default displays the name field.
I have two cases where I wish to have something other than the name display:

A Users custom relate field on Opportunities where I wish to display user_name instead of name.

A Cases custom relate field on Cases (stores the Parent Case) where I wish to display case_number instead of name.

I would want all occurrences of the field, including SQS, to show the user_name/case_number respectively instead of the name.

Is this possible?