motion path problems

Hi everybody,

I created this motion path interaction:
arrow down moves the group down on motion path 1 / arrow up moves the group up on motion path 2

Each button should move the group only to specific position and then should become disabled or stopped so that the object doesn't dissapear from the screen with the next click on the same button.

How can I force these buttons to move the group to specific position and not any farther?

Also how can I make the group come back to initial state when user clicks elsewhere or moves to another object on slide?

Thank you for any suggestions and help
Tom