can't find "this" in jquery overlay

can't find "this" in jquery overlay

New to jquery and using the overlay tools in jquery-1.2.7.tools.min.js.  I have several div's set up as overlays on an 'img' and some 'a' tags. 

    <img src="/image/test.png" rel="#1485">
    <div id="1485" class="simple_overlay">
        <a rel="1486">1</a>
        <a rel="1487">2</a>
        <a rel="1488">3</a>
    <div id="1486" class="simple_overlay">
        <a rel="1486">1</a>
        <a rel="1487">2</a>
        <a rel="1488">3</a>
    <div id="1487" class="simple_overlay">
        <a rel="1486">1</a>
        <a rel="1487">2</a>
        <a rel="1488">3</a>

When I click on one of the 'a' links, I want the overlay div matching its id to be shown, and the others to be hidden.  But, in using jquery code like this:

    <script>
        $(document).ready(function () {
            $('img[rel]').overlay({
                oneInstance: false
            });
           
            $('a[rel]').overlay({
                oneInstance: false,
                onLoad: function (event) {
                    $('.simple_overlay').not($(this)).hide();
                }
            });
        });
    </script>

or in using this:

    $(this).siblings().hide()

the "this" designation does not do what I want.  Essentially, all divs with class .simple_overlay are hidden on the hide() call.  I want the div with the clicked rel id to be shown, and the others hidden, but it seems I'm mistaking what "this" is...Can anyone tell me how to do this?