Using a Custom Field like a tag

On my blog — https://www.sixwordstories.net — I use a Custom Field called “Author” on each post, to specify the author (each is a six word story).

I, the admin, submit every post, and we have hundreds of authors, so it doesn’t make sense to use the WP User/Author capabilities for this.

I would like to somehow treat this Custom “Author” Field as if it were a tag; I’d like to create an “Author” tag cloud, and also list the posts by each author in its own section (just as if it were a tag).

Using built-in tags to keep track of the authors won’t work, because I use the tags for another purpose. I don’t want the authors’ names to mix in with the other tags.

Any suggestions on how to do this?