Surnames in YAML header of R Markdown documents

In the YAML header, when typing in an author's name (e.g., Jonathan Callum Barnes), is there a way to specify aliases and/or to specify a particular part of the author's name to be used for indexing purposes? As an example, defining the surname (Barnes) as an index by which posts, etc. should be categorised? I feel it's a bit cumbersome to index by an author's full name and I want a way to quickly refer to (and categorise by) individual authors without having to give their full name.

What do you mean by index ? Are you using PDF output ?

What would you expect ?

I am not familiar with all this I think, so I need to understand better before trying to answer

Sorry, I should clarify: I mean in the context of, say, a blog or website where a post (or page) might have multiple authors, with authors mentioning other authors in text. So, if "Ursula K. Le Guin" were a contributor to the site, if I were to mention "Le Guin" in a post, the site would know that "Le Guin" is the index term being used to refer to that particular contributor and clicking on their name would link to a page listing all their contributions to the site (posts, etc.). So, "for indexing purposes," I mean specifying that a particular part of an author's full name is the accepted shortened form for referring to them on the site.

Thanks for the precision.

How do you create an index usually ?

I really don't know how to do what you are describing, maybe others will know