How would I tag a user through a post to RingCentral WebHooks?

Ex.

{ "activity":"Beer consumed", "title":"Jeff is having a Maple Bacon Coffee Porter", "icon":"https://static.skillshare.com/uploads/project/239dbec8bcc75f80457b1caa47a4a657/a801f44f", "body":"* Location: [The Funky Buddha Lounge](http://www.thefunkybuddha.com) with @username"}

When the above message is posted to WebHooks, I would want it to tag the user "@username" and notify them as if a normal user was to tag them in a message. The example above doesn't seem like the correct way to go about doing this.

Thanks in advance! :)