This is going to be a bit technical, apologies...
Right now, we strip any Reply-to header from an incoming message. In most instances, we generate a new, appropriate reply to. But for groups that have the reply to setting set to either Reply To Sender or for messages that are tagged with a tag that is set to Reply To Sender Only, we end up not generating a replacement Reply-to header.
A group owner sets the Reply-To header on messages he sends to his announcement group, and would like those headers preserved. I can make that happen by not stripping the incoming Reply-To for groups set to Reply To Sender Only (or tagged appropriately). I don't think this will change behavior for anyone, but I'm not 100% certain. So can anyone think of a reason not to do this?