Syncing gauge chart (clock) with floating bar chart

HTML

<script type="text/javascript" src="http://www.amcharts.com/lib/3/amcharts.js"></script>
<script type="text/javascript" src="http://www.amcharts.com/lib/3/serial.js"></script>
<script type="text/javascript" src="http://www.amcharts.com/lib/3/gauge.js"></script>
<div id="chartdiv2"></div>
<div id="chartdiv"></div>

CSS

#chartdiv {
	width	: 60%;
	height	: 300px;
    float: left;
}
#chartdiv2 {
	width	: 39%;
	height	: 300px;
    float: left;
}

JavaScript

/**
 * Floating chart
 */
var chart = AmCharts.makeChart("chartdiv", {
	"theme": "dark",
    "type": "serial",
    "dataProvider": [{
        "name": "John",
        "startTime": 8,
        "endTime": 11,
        "color": "#FF0F00"
    }, {
        "name": "Joe",
        "startTime": 10,
        "endTime": 13,
        "color": "#FF9E01"
    }, {
        "name": "Susan",
        "startTime": 11,
        "endTime": 18,
        "color": "#F8FF01"
    }, {
        "name": "Eaton",
        "startTime": 15,
        "endTime": 19,
        "color": "#04D215"
    }],
    "valueAxes": [{
        "unit": ":00",
        "axisAlpha": 0,
        "gridAlpha": 0.1,
        "guides": [{
            "value": 0,
            "above": true,
            "lineColor": "#c00",
            "lineThickness": 3,
            "lineAlpha": 0.5
        }]
    }],
    "startDuration": 1,
    "graphs": [{
        "balloonText": "<b>[[category]]</b><br>starts at [[startTime]]:00<br>ends at [[endTime]]:00",
        "colorField": "color",
        "fillAlphas": 0.8,
        "lineAlpha": 0,
        "openField": "startTime",
        "type": "column",
        "valueField": "endTime"
    }],
    "rotate": true,
    "columnWidth": 1,
    "categoryField": "name",
    "categoryAxis": {
        "gridPosition": "start",
        "axisAlpha": 0,
        "gridAlpha": 0.1,
        "position": "left"
    }
});

/**
 * Clock
 */

var chartClock = AmCharts.makeChart("chartdiv2", {
    "type": "gauge",
	"theme": "none",
	"startDuration": 0.3,
    "axes": [{
        "axisAlpha": 0.3,
        "endAngle": 360,
        "endValue": 12,
        "minorTickInterval": 0.2,
        "showFirstLabel": false,
        "startAngle": 0,
		"axisThickness": 1,
        "valueInterval": 1,
        "labelOffset": 5,
        "inside": false,
        "bands": [{
            "color": "#FF0F00",
            "endValue": 11,
            "startValue": 8,
            "innerRadius": "80%",
            "alpha": 0.8
        }, {
            "color":...