Display posts in threaded format

I am hoping to start a website where one author writes a post, and then a series of other authors respond throughout the week (like a long conversation in post form). Instead of having the posts display like a regular blog, one on top of the other, I want to group the related posts together. So, for instance, Post #1 would show in full, with Post #1 Response #1, Post #1 Response #2, etc. showing as excerpts next to it.

Is this possible in WordPress (or elsewhere if you know)? Is there a way to group and display posts as a thread, similar to a forum? Or some way to set a main post as a target, or something?

I was thinking using a Related Posts plugin, and using a common tag for all the post/responses, but that seems really inelegant and open to disaster if the system thinks some unrelated post is actually related. Plus it means that I couldn’t use related posts for its intended purpose if I wanted.