Thank you all for your replies. I ended up duplicating the video tracks, crating a title with an ellipse around my subjects, placing a track matte on Video 2, Matte to Video 3 which is the title, then did a gaussian blur on the bottom track. I can now move the title ellipse around as my subjects move around the screen. This keeps all but the ellipse track matte clear while keeping the background blurred.
Thanks again