I had this happen on hires I was responsible for, but on "continuously open positions" or when the position is left vacant and the headcount repurposed to another position.

I didn't find a useful or correct way to inform all the potential candidates about that change. That happened two times and I only sent the more generic e-mail we send for rejection telling the people that had had at least one face to face to apply for other positions if they were still interested in the company.

For the easier case of filling the headcount up with someone and not wanting the rest it's easier to send a rejection e-mail, it's just not what always happens with every job opening.