You just have two divs with different speed of animation, like this:
HTML
<div class="one"></div>
<div class="two"></div>
jQUERY
$('.one').animate({top:100}, 500);
$('.two').animate({top:200}, 1000);
That's it, you need to set the proper top
of course based on the height of the divs (get that dynamically).