Display a user's signature only once per topic

Our community members have requested that we reduce the number of signatures displayed in topics. They feel it can too easily ‘clutter’ a topic/thread, especially the super long ones with hundreds of replies.

They’ve asked that the topic creator’s signature is shown once, at the beginning, but not in his/her replies. 

And that it only shows in the first reply for all other users who post in the same topic.

(So for each topic, each contributor’s signature will only appear once.)