Disable generating post single URL or prevent from crawl

Suppose, I have a post category called XYZ. I already posted 3 different posts to this category.

These are as follows

1st posts - www.example.com/2015/04/20/1st-posts/
2nd posts - www.example.com/2015/04/20/2nd-posts/
3rd posts - www.example.com/2015/04/20/3rd-posts/

I already showing them in a page called MNO and the titles are not linkable. So, users can’t see the single view of the posts. That’s fine. But, I can view them as a single posts by opening these URLs in browsers and search engines also crawling these posts URLs. For search engines, people are coming to these pages although these posts title are not clickable on the MNO page.

Now, My question is –

1. Can I prevent crawling? Or,

2. Can I remove these URLs and post content will be available for MNO page too?

3. Which will be the best way to do? .htaccess or any other way?

N.B. Actually, I can’t move to any custom post types or own created plugin. Because, there are at least 5000 posts.