It happens, but the companion cannot be a duplicate article while the other is still active (usually four hours.) And posters can link back to the original, caucused thread, to wave off anyone not wanting the contention of an “open” RF thread, town square type debate.
These threads go on for days. Four hours is not long enough.
As Judith pointed out below, four hours is meaningless with the thread like this (also, news out of the Vatican can easily be sourced from multiple news agencies and this makes the point about duplication moot).
These threads typically go on UNTIL a new thread is chosen. The subject of thread is generally ignored after the first few dozen posts and all we hear are the same old talking points. Take the threads about clerical abuse, what significance do Marian or Eucharistic beliefs have to do with them? The answer is nothing, but it still gets talked about. How many times has it been stated that when we speak of our Lady of Fatima that Fatima is the name of town in which she appeared, not her name? It happens on every thread and the reason is almost certainly that an unmentionable hate monger once published a "tract" stating that we were talking about Mohammed's daughter.