@cyberczar Your replies will only go back to the person you reply to (in most recent versions of GNU social it should end up at all the recipients of the sub-thread you're writing to, but not necessarily in their home timeline).
Throwing everything explicitly back to the group would make the conversations complete, but as I mentioned it does have the sideeffect of bumping up the thread also for people not necessarily interested in that specific _part_ of the discussion :)
Conversations are hard.