There is a category wide “Navigate to first post after topics are read” setting. When enabled, users will be taken to the first post in a topic if they revisit the topic after having read all of its posts. This setting cannot be applied to just the category’s About topic though.
For your case, moving the replies and then closing the topic might be the best approach. To move the replies, click the topic’s admin wrench, then choose ‘Select Posts’ from the admin menu:
After selecting the posts, you’ll be given the option to move them to a new or existing topic.