Sync Scroll 2 editor instances

I have an application that needs to show two editor instances side by side and synchronize scrolling between the two. I can do this with 2 textareas, but the JS code won't apply to ckeditor instances. Any suggestions?

    <script type="text/javascript">
        $(function() {
            $('textarea[id$=tb1]').scroll(function() {
                $('textarea[id$=tb2]')
                .scrollTop($('textarea[id$=tb1]').scrollTop());
            });
        });
    </script>