Don’t move the camer

 Don’t move the camera (during the shoot).  Shoot five separate passes, one for both of you playing each instrument, you can then composite the layers and add ‘camera’ motion in post.  There are YouTube videos with some examples like this:

http://www.youtube.com/watch?v=-Lnw6NhY6j0

or this:

http://www.youtube.com/watch?v=b3W0wTD-nl0&feature=channel_video_title