We've been planning to post a video of the dogs but just now got around to it. Charlie is usually the instigator of the "fights" as you can probably see in the video above. Notice how Hutch goes to Jason when he realizes we're watching them. Charlie, however, goes after Murphy (the camera ran out of memory space after this).
In the 2nd video, taken last night, Charlie was trying to start something with Hutch but as soon as I started videotaping he played dumb :-)