Redirect answer to post from webhook back to webhook

I have an integration that posts something into a channel (a new question has arrived) and I’d like to have an easy way to answer that question right from Mattermost. Is that possible? (preferably across channels)

They most intuitive way would be to let the user reply to that post and redirect the reply to my webhook so it can add it as answer or comment in the Q&A.

Any ideas how to accomplish that?

You could ask your users to write answer: at the start of it and make the hook filter that?

Or some other key.

I have a similar situation. The incoming webhook adds text to the channel. But even if that text has the trigger word exactly as the first word, the outgoing webhook isn’t triggered.