how to add marker cluster in google maps v3 for th

I made traceroute map. And I have problem with some markers that should be in the same lat/long but only one marker show on the map. I read that there's a way to do. It is marker cluster. but I don't know how to add in javascript. Also I'm afraid if that would be influent another element of markers which I've add like custom marker with label, infowindow and polyline. here is my code :

<script type="text/javascript">
    var pinImage = new google.maps.MarkerImage ("http://chart.apis.google.com/chart?chst=d_map_xpin_letter_withshadow&chld=pin_star|%E2%80%A2|CC3300|000000|FF9900",
        new google.maps.Size (70, 83),
        new google.maps.Point (0,0),
        new google.maps.Point (10,34));
    var pinShadow = new google.maps.MarkerImage ("http://chart.apis.google.com/chart?chst=d_map_pin_shadow",
        new google.maps.Size (89, 85),
        new google.maps.Point (0, 0),
        new google.maps.Point (12, 35));

    function initialize() {
    var myLatlng = new google.maps.LatLng(38.822591, 150.46875);
    var myOptions = {
    zoom: 2,
    center: myLatlng,
    mapTypeId: google.maps.MapTypeId.ROADMAP,
    }
    var map = new google.maps.Map(document.getElementById("map_canvas"), myOptions);
    <?php
    $posisi = array();
    $keterangan = array();
    foreach ($integer as $lokasi) {
    $query = "SELECT cl.locId, cl.country as country, cl.region as region, cl.city as city, cl.postalCode as postalCode, cl.latitude as latitude, cl.longitude as longitude, cl.metroCode as metroCode, cl.areaCode as areaCode
    FROM (SELECT locId as idcihuy FROM cityblocks WHERE $lokasi BETWEEN startIpNum AND endIpNum) cb, citylocation cl WHERE cb.idcihuy = cl.locId";
    $result = mysql_query($query);
    while ($location = @mysql_fetch_assoc($result)){
    $posisi[]= 'new google.maps.LatLng(' . $location['latitude'] . ', ' . $location['longitude'] . ')';
    $keterangan[]= '"(' . $location['country'] . ',  ' . $location['region'] . ',  ' . $location['city'] . ')"';
    }
    }
    ?>
     var infoWindow = new google.maps.InfoWindow({});
     var point = [<?php echo implode(',', $posisi) ?>];
     var lokasi = [<?php echo implode(',', $keterangan) ?>];
     var icon = pinImage;
     for (var i = 0; i < point.length; i++) {
     var html = "<b>" + lokasi[i] + "</b> <br/>" + point[i];
     var marker = new MarkerWithLabel({
        map: map,
        position: point[i],
        icon: pinImage,
        shadow: pinShadow,
        labelContent: i,
        labelAnchor: new google.maps.Point(12, -5),
        labelClass: "labels"
        });
        bindInfoWindow(marker, map, infoWindow, html);
    var jalur = new google.maps.Polyline({
    path: point,
    strokeColor: "#000000",
    strokeOpacity: 0.8,
    strokeWeight: 2.25
    });
    jalur.setMap(map);
        }
        }
    function bindInfoWindow(marker, map, infoWindow, html) {
      google.maps.event.addListener(marker, 'click', function() {
        infoWindow.setContent(html);
        infoWindow.open(map, marker);
      });
    }
    </script>

Also I give you the sample of positions which have the same lat/long :

[
 new google.maps.LatLng(1.3667, 103.8000),
 new google.maps.LatLng(1.3667, 103.8000), 
 new google.maps.LatLng(1.3667, 103.8000),
 new google.maps.LatLng(1.3667, 103.8000),
 new google.maps.LatLng(51.0000, 9.0000),
 new google.maps.LatLng(51.0000, 9.0000),
 new google.maps.LatLng(51.5142, -0.0931),
 new google.maps.LatLng(51.5142, -0.0931),
 new google.maps.LatLng(54.0000, -2.0000),
 new google.maps.LatLng(51.6000, -1.2500),
 new google.maps.LatLng(51.7500, -1.2500)
];

I need the help to make the marker cluster for same lat/long but that would not influent another element like marker with label, infowindow and polyline. Please Help. Thank You.

You can use this library.

MarkerClusterer for Google Maps v3

The library creates and manages per-zoom-level clusters for large amounts of markers.

Example

When you zoom in on a cluster you can see multiple markers in one location.

EDIT:

// GET AN EMPTY ARRAY
var markerArray = [];
for (var i = 0; i < point.length; i++) {

    // CODE AT THE BEGINNING OF LOOP

    var marker = new MarkerWithLabel({
        // MARKER CONFIGS
    });
    markerArray.push(marker);

    // REST OF THE CODE IN LOOP
}

// TIME FOR ACTION
var markerCluster = new MarkerClusterer(map, markerArray);