Show excerpts in archive but protect the individual posts

I need the home page to be visible as it is. But when a person clicks on the Read More link on any blog’s excerpt or tries to open a post, this access should only be for Registered/Paid Accounts.

I can see I can hide parts of content of a post using. If I want my existing blog of 2600 posts to be all paid content I would have to go into each post and do this or maybe add the shortcode in the template with some tweaks.

Please add this as feature request.