In theory, yes that would be possible. But is it necessary? Do you have any sense of what @Stephen had in mind in his comment above when he said “the wiki is always the first post in the topic”? Did he and I just miscommunicate?
It’s usual to make the OP the wiki post, though it does work on any post. But if you make eg. post 40 in a topic a wiki, it won’t change its place in the post order.
@JammyDodger Thanks again. I think that clears up the issue for the future. Going forward, we’ll create a post right after the OP as a placeholder for a future wiki post that would contain any updates.
Unfortunately, that won’t help us for our past posts that need the same thing. Do you have a suggestion for how we could slip a post into an existing sequence in the #2 position?
If there are only a few, and they don’t have reams of replies, you could consider moving all the replies to a new topic (using the topic wrench ‘select posts’), adding a new one below the OP, and then moving them back (plus a little clean-up of the small post actions). It would send out some notifications though, so may be quite ‘noisy’.
Though I feel like I’m missing something obvious. 
Can anyone else think of a more elegant solution?
@JammyDodger Unfortunately, we have more than a few, and they have many replies. So I don’t think we’ll adopt that approach.
Does anyone have another solution for inserting a post in the #2 position into an existing sequence of posts?
Sorry for the bump, but 4 years later I am still wanting for precisely what OP described.
On our board, we have a lot of Feedback topics that are mostly just discussions. The first year and on a curve afterwards, there wasn’t much organising going on, so not unusual to see 15 topics on the same subjects.
With these, my routine is to find as many as I can, and merge them all together. However I want to have the post that represents the subject the best to be the main header, always on top. This to preserve credits towards the OP, and to preserve the date as well.
Because sometimes, I will have to work the unability to pin by changing the timestamp of the post I want to spearhead the topic with, so I’ll reset that timestamp to a date that will maintain its position as the first post, when merging starts.
- Using the “solution” plugin is not a good option for us
- Changing the timestamp is something I kinda really don’t want to do, even though I sparingly do it
- Here is an example for such a topic, where lots of merging happened: Respec costs - give players a choice - Wicked Feedback - No Rest For The Wicked
Anyone any ideas how to solve this best, for our use cases?
Silas
edit: also why I bumped this, it’s the first topic in Google Search right when I look for this exact feature 
I think you can check this out, it offers something really similar (or the feature as is):