How about this?
http://jsfiddle.net/P7c9q/4/
.relative{
position:relative;
}
.absolute {
position:absolute;
width: 40px;
height: 100px;
background: #000;
z-index: 1;
top:30px;
left:0px;
}
.yellow-div {
position:relative;
width: 200px;
height: 50px;
background: yellow;
margin-bottom:4px;
z-index:0;
}
use the relative div as wrapper and let the yellow div's have normal positioning.
Only the black block need to have an absolute position then.
