The way you’ve ‘deployed’ this is very unconventional. You should have just set your post page to be the ‘News’ page.
However, to answer your question. In appearance > menus > select menu you would like to edit, you can use something known as custom links, in which you can then add the same title as your www.xyz.com site, with the link from www.xyz.com over on your www.xyz.com/news site.
