Here's what the closed-as-duplicate message looks like:
marked as duplicate by johndoe1, johndoe2, johndoe3, johndoe4, johndoe5 May 5 '55 at 5:55
This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.
Or something like that. Anyway, 'has been asked before' implies that the other duplicate is older, while apparently the most relevant one should be left open, and the other one closed as duplicate. That means the newest question may be the one left open, and the older question marked 'has been asked before' with a link to a newer question.
Is that fine with everyone else? It seems like we could change it with a more accurate message.