set a variable say _root.where_now , in the button action
so eg for the button that links to scene_1
_root.where_now = scene_1 ;
now in the frame that your fadeout ends, add an action
e.g. use the variable you set onclick to decide which frame to goto ... if my syntax is back to front I apologise, setting the variable as at the root seems to stop most variable scoping issues.