Factual note: Switzerland joined the UN a couple of months ago.
Second factual note: It is absolutely, totally legally impossible not to accept EU citizens as workers. It is also illegal (for reasons of UK law, not EU regts) to favour any group over another, so long as the person in question have a work permit and is better qualified than the other candidates. It should be obvious that choosing people by their professional ability ensures getting the best people; any other criterion is inefficient, quite apart from being morally wrong.