If you right-click on a link (Windows, someone else will have to answer if you're using a Mac) you get the option, Open Link in New Tab. WikiTree internal links to another profile are normally done as [[Doe-1 | John Doe]], giving you an underlined link reading "John Doe." But you could use any text you like in that construction to make a link. For example, [[Doe-1 | his father]] could be used in the bio of his son, giving the text "his father" and linking to his father.