I don't know that it is possible without a gap or pause.
Option A: (fun to think about but stupid) - make each chapter start with the menu as the button is clicked - a sort of motion menu/transition video, except it is the actual chapter video and zooms out and continues play. The problem - when you play the whole timeline/play all, there are all of these menu/chapter zooms in there!
Option B: Transition: when you click the button, a transition plays that does what you described up to the point that the chapter plays. Somewhere, the transition must end and the chapter begin. This will work if the chapter begins with something generic like a fade up from black. And the problem: there will probably be at least a small gap/pause before the actual chapter plays.
Encore does not do scripting; somlewhere I got the impression that you can improve pauses via scripting, or does that have more to do with how assets are allocated on the disk.
