[MM3-users] Thread IDs on messages incrementing per reply?

Trying to use the thread prefix component to *tag* thread IDs in a system, but not increment per message.

It looks like replies are being received and then thread prefixes are getting incremented. "[Test-%07d]" is the prefix I"m using on a given test list, but we want it to increment by thread ID and *not* per message.  (6 messages for instance have been sent, two were replies to [Test-0000004] and though the system properly archived it in the same conversation, it still incremented the digit counter).

Is there a way to achieve this in Mailman3 without me having to write some kind of custom code for this?

Thomas