Hey there notionist. This isn’t doable particularly easily using the built in “URL” option for Additional Fields, but there’s a trick that should work for you here and is pretty easy. If you set up “URL” or “Website” field, but select TEXT instead of URL as the type, it’ll allow you to write your URLs as basic HTML.
This means you can add something like http://d.pr/i/dHpY on the backend, and it’ll publish on the frontend as “CNN” (http://d.pr/i/wR2E).
That help?