There’s a third-party tool you can usually use: lemmyverse.link

So pop the url of the post on the home instance in, and you get lemmyverse.link/sh.itjust.works/post/31943808

Once you’ve set your home instance, it will divert you to the home instance’s post.

Unfortunately there isnt a way that i know of that lets you do it in lemmy. I think adopting sharing links via lemmyverse.link is the way forwards at the moment.