It might not be possible, depending on how IDs a created for posts.
It might be better to simply allow apps to do it, but battery optimization will affect it.
But it is a functionality that I've also wanted for a while now. Because now you are just limited to single posts and the character limit. Which in turn can be a good thing, because #instances have character limits for reasons. Which #threads basically make obsolete but it still allows for more granular control.
But good luck getting #Mastodon to accept pull requests. If it were easy, all functionality of #Megalodon would be in the official app.