If you don't care about the compatibility with older IE versions (< 8), you could make a custom jQuery plugin and then call it on the overflowing element.
This solution has an advantage over the one Šime Vidas proposed, as it doesn't overwrite the scrolling behavior - it just blocks it when appropriate.
$.fn.isolatedScroll = function() {
this.bind('mousewheel DOMMouseScroll', function (e) {
var delta = e.wheelDelta || (e.originalEvent && e.originalEvent.wheelDelta) || -e.detail,
bottomOverflow = this.scrollTop + $(this).outerHeight() - this.scrollHeight >= 0,
topOverflow = this.scrollTop <= 0;
if ((delta < 0 && bottomOverflow) || (delta > 0 && topOverflow)) {
e.preventDefault();
}
});
return this;
};
$('.scrollable').isolatedScroll();