It's not about drafting the clause, but the repugnant clause itself. Whether you are an HR or other management professional, just think about some "niche segments" like publishing, media, broadcasting (TV, FM), etc. Where would you think a TV anchor, an editor/sub-editor, graphic designer, etc., would get their next job?
Just think: A newspaper fires a sub-editor. Now where should the sub-editor find a job? Of course, in the newspaper industry itself! A clause like the one you are proposing would mean that the 'fired' sub-editor should look for employment in mining or infrastructure or the energy sector, anything but in 'publishing'.
Similarly, a 'fired' or 'resigned' air-hostess should seek her next employment not in any competing airlines but perhaps as a receptionist in a hotel or office! Forget about one's experience or expertise as an HR person; simply as a rational person, do you think such a situation is justified?
Warm regards.