Most Nepleslia JPs were like this, roughly 8+ people at a time, no posting order whatsoever.
While, at times, it was indeed hard to follow (and made OOC channels absolutely necessary), most of the work was up to the editor to sift through and move paragraphs so that they fit the conversations. I became quite skilled at it for a while myself, but while it can be chaotic, it does have rewards of its own...namely, the ability for multiple people to hold multiple conversations, with little chance of getting derailed.