html - Hide block which does not fit container height

Question

I have example here http://jsfiddle.net/brain2xml/cVAMN/

<div id="container">
<div class="sep">1</div>
<div class="sep">2</div>
<div class="sep">3</div>
<div class="sep">4</div>
<div class="sep">5</div>
</div>

and css

.sep{
    border:1px solid red;
    height: 50px;
    width: 280px;
    margin: 10px;
}
#container{
    height: 170px;
    width: 300px;
    border:1px solid green;
}

I want blocks (block 3, 4 and 5) inside container been hide if they not whole inside container. If I put overflow property to container, the half of block #3 still visible. But I want show blocks if they whole visible in container.

Is it possible to do without js?