Using RegExp to dynamically create a Regular Expression, and filter content

I am struggling with using the RegExp object to allow me to dynamically create an expression, and apply it to a group of elements.

Here is a jsFiddle, below is the code:

<div id='selectors'><span>A-F</span><span>G-L</span><span>M-S</span><span>T-Z</span></div>

<a hreh=#>Astring</a>
<a hreh=#>Cstring</a>
<a hreh=#>Xstring</a>
<a hreh=#>Dstring</a>
<a hreh=#>Zstring</a>

$('div#selectors span').click(function(){
        expression = "/^["+$(this).html()+"].*$/";

        rx = RegExp(expression,'i');
        console.log(rx,'expression');
        $("a").each(function(){

                    if($(this).html().match(rx) !== null){
                        $(this).addClass('selected');
                    }
        });

    })