Add external attachments without amendment

Is there a way to allow external attachments without having to amend a negotiation? Because the negotiation messaging feature does not allow public viewing of responses to all participants, we have to upload Q&A attachments periodically, and an amendment is required every time. This is a huge burden not only requiring approval, but the suppliers have to also re-acknowledge participation and submit their responses again every time there's a amendment.

Can you please provide guidance with adding external attachments without having to amend the negotiation?