Propagation happens in the DOM, it can only be on or off for the whole element, not for a specific event handler.
My suggestion: compare the current element with the click target:
function fn_stoppropagation(e){
if (this===e.target) {
// the following will only run for the target, not its ancestors
alert('stoppropagation '+$(this).attr('id')+' called');
}
}