Bar graphs can be grouped / ungrouped. The responses will have to made according to that.
{xlabel: "Months",ylabel: "Sales",grouped: true,group_labels: ["1st Week", "2nd Week", "3rd Week", "4th Week"],data=[{ label: "Jan", values: [300, 400, 350, 370] },{ label: "Feb", values: [300, 400, 350, 370] },{ label: "Mar", values: [300, 400, 350, 370] },{ label: "Apr", values: [300, 400, 350, 370] },{ label: "May", values: [300, 400, 350, 370] },// ...]}