How do I make Flexslider2 start with a specific slide depending on URL link?

<div class="controls">
   <a href="http://www.example.com/#slide1"><img id="slide1" src="http://www.example.com/img1.jpg"/></a>
   <a href="http://www.example.com/#slide2"><img id="slide2" src="http://www.example.com/img2.jpg"/></a>
   <a href="http://www.example.com/#slide3"><img id="slide3" src="http://www.example.com/img3.jpg"/></a>
   <a href="http://www.example.com/#slide4"><img id="slide4" src="http://www.example.com/img4.jpg"/></a>
</div>

<div class="flexslider">
   <ul class="slides">
     <li><img id="slide1" src="http://www.example.com/img1.jpg"/></li>
     <li><img id="slide2" src="http://www.example.com/img2.jpg"/></li>
     <li><img id="slide3" src="http://www.example.com/img3.jpg"/></li>
     <li><img id="slide4" src="http://www.example.com/img4.jpg"/></li>
   </ul>
 </div>

$('.flexslider').flexslider({
        animation: "slide",
        animationLoop: false,
        itemWidth: 200,
        itemMargin: 0,
        minItems: 1,
        maxItems: 2,
        useCSS: false,
        move: 2,
        slideshow:false,
        controlNav:false,
        directionNav:true,
        touch:true
     })