How do you change the Page Open default?

All of my links now need to open in a new window. However, the page default has them all opening in the same frame. I have to manually change the setting for every link by going into Properties>Advanced and clicking New Window from the dropdown.

I changed that setting on one link, and looked into the HTML code to see the command. But there didn't appear to be any way I could use that command (target="_blank) in a Search and Replace function in each project because I need to insert it into the hyperlink code, which is always unique. "Search and Replace" was Plan B when I couldn't find any way to change the setting in the project. How do I do this? I have a massive number of links to update with this command. I really need to automate it. Thanks!

CODE TO OPEN IN NEW WINDOW

<a href="http://portal.hud.gov/huddoc/13-01ml.pdf"

              target="_blank">HUD Mortgagee Letter 2013-1</a>

CODE TO OPEN IN SAME FRAME

<a href="http://portal.hud.gov/huddoc/13-01ml.pdf">HUD

Mortgagee Letter 2013-1</a>