Adding links to a pdf & want underlining, NOT complete visible rectangle around the text. Is there a way?

I'm adding links to a pdf, but I'm only seeing the option to have a complete rectangle around the linked text (visible rectangle) or nothing (invisible rectangle). Does anyone know if there's an option just to underline the text so people know there is a link there? I don't like the appearance of the full rectangle, but I don't want to leave it with nothing. Thanks!