一个legend里有多张图表,如何设置legend和series里的data?

描述:当前是关于Echarts图表中的 折线图 示例。
 
            option = {
    title: {
        text: 'Awesome Chart'
    },
    legend: {
        data: [{
            name: '增量' //first legend
        }, {
            name: '增速' //second legend
        }]
    },
    xAxis: [{
        gridIndex: 0,
        type: 'category',
        data: ['1月-3月', '4月-6月', '7月-9月', '10月-12月']
    }, {
        gridIndex: 1,
        type: 'category',
        data: ['1月-3月', '4月-6月', '7月-9月', '10月-12月']
    }],
    yAxis: [{
        gridIndex: 0,
        type: 'value',
        name: ''
    }, {
        gridIndex: 1,
        type: 'value',
        name: ''
    }],
    grid: [{
        show: false,
        left: '10%',
        top: '10%',
        containLabel: true,
        width: '30%',
        height: '35%'
    }, {
        show: false,
        left: '50%',
        top: '10%',
        containLabel: true,
        width: '30%',
        height: '35%'
    }],
    //this is the first legend's series data,
    //how to set the second legend's series data?
    series: [{
        name: '增量',
        type: 'line',
        xAxisIndex: 0,
        yAxisIndex: 0,
        label: {
            normal: {
                show: true,
                position: 'top',

            }
        },
        data: [56, 90, 98, 151]
    }, {
        name: '增量',
        type: 'line',
        xAxisIndex: 0,
        yAxisIndex: 0,
        label: {
            normal: {
                show: true,
                position: 'top',

            }
        },
        data: [48, 152, 160, 165]
    }, {

        name: '增速',
        type: 'line',
        xAxisIndex: 1,
        yAxisIndex: 1,
        symbolSize: 8, //拐点大小
        label: {
            normal: {
                show: true,
                position: 'top'
            }
        },
        data: [23, 58, 97, 106]
    }, {

        name: '增速',
        type: 'line',
        xAxisIndex: 1,
        yAxisIndex: 1,
        symbolSize: 8, //拐点大小
        label: {
            normal: {
                show: true,
                position: 'top'
            }
        },
        data: [10, 85, 98, 105]
    }]
};