How to make specific category post links open in a new window?

I am using a post attachment plugin and I made it redirect to file url if attachment exist. So if there are any attachment with a post, it will be redirected to file url. But I don’t want it to open in the same window. Is there any system where I can set specific post or post of a specific category links to open in a new window?
I can’t use target=”_blank” as the links are on category archive page or recent posts widget and recent post list type plugin.