Technically yes, but this one is anything but easy, since there is no "Wordpress frameset", especially if you want the frameset to look like Atahualpa and have Wordpress functionality. And many target sites will probably break out of your frame with a Javascript framebuster anyway. I'd not use frames at all.
If you still want to try, the page with the frameset, i.e. frameset.php would look similar to this
<FRAMESET cols="20%, 80%">
<FRAME src="http://www.mydomain.com/contents_of_left_frame.html">
<FRAME src="<?php echo $_GET['link']; ?>">
<NOFRAMES>
<p>Your browser doesn't support frames.
This frameset document contains this page:
<a href="<?php echo $_GET['link']; ?>">
</p>
</NOFRAMES>
</FRAMESET>
And the link would be <a href="frameset.php?link=http://www.othersite.com/">
with
http://www.othersite.com/ being the site that is supposed to be framed