Channel Forms: Relationship Field fetching field other than title for selection

{options:additional_riders}
          <input type="checkbox" name="additional_riders[data][]" value="{option_value}" {checked}/>
          {option_name}

          {/options:additional_riders}

The above template code correctly shows the relationships as checkboxes with the relationships {title} as the text next to the checkbox. But what if I want to use another custom field as the option_name!!! WHA!!!

Any Tips

Thanks