Maybe if I try being a bit more verbose. There's two different things here to consider. Either you want to quote multiple posts like this:
Jim's post
Lets call it flat quoting of multiple posts. This is what the multi-quote feature is for.
But what I think you want to achieve is to quote a post with all the posts this post might have quoted before. Like this:
Jim's post
Let's call it nested quoting. This is what the old forum software did automatically, but they didn't want this feature in the update for reasons I won't go into here. So the only way to do this know (AFAIK) is to add it manually in your post.