Aligning C3 line shapes with Bar charts

Question

We have the following mixed line chart / bar chart in C3:

• a bar chart with two groups (light/dark blue is one group, gray is the other group)

• two other data sets represented as line with stroke-width = 0 that represent the limit for group1 and group2.

How can we place the circle shape for line1 aligned with the bar for group1 and the circle shape for line2 aligned with the two bars of group2?

In the following example, we basically would want one of the two circles to be moved slightly to the right so to align with the center of a group and the other one slightly to the left.

var chartSettings = {
        padding: {
            left: 120,
            right: 120
        },
        bindto: '#chart',
        data: {
            x: 'Dates',
            type: 'bar',
            types: {
                line1: 'line',
                line2: 'line'
            },
            groups: [
                ['data2', 'data3'],
            ],
            colors: {
                data1: '#f3e274',
                data2: '#85bdde',
                data3: '#ccebfb'
            },
        },
        bar: {
            width: {
                ratio: 0.50 
            }
        },
        point: {
            r: 8
        },

        axis: {
            x: {
                type: 'timeseries',
                tick: {
                    format: '%d-%m-%Y'
                }
            },
            y: {
                label: { // ADD
                    text: '',
                    position: 'outer-middle'
                },
     
            },
        }
  };
  
  var date1 = new Date(2015, 1, 1, 0,0, 0,0);
  var date2 = new Date(2015, 3, 1, 0,0, 0,0);
  var date3 = new Date(2015, 6, 1, 0,0, 0,0);
  var xAxis = ['Dates', date1, date2,date3];
  var line1 = ['line1', 50, 60,55];
  var line2 = ['line2', 70, 75,60];
  var data1 = ['data1', 40, 35,30];
  var data2 = ['data2', 5, 10,10];
  var data3 = ['data3', 20, 15,30];
  chartSettings.data.columns = [xAxis,
            line1,
            line2,
            data1,
            data2,
            data3];
 c3.generate(chartSettings);

#cr-chart .c3-line-accordatoTotale {
    stroke-width: 0px;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.4.11/d3.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/c3/0.4.11/c3.min.js"></script>
<div id="chart"/>

var  chartSettings = {
        bindto: '#chart',
        data: {
            x: 'Dates',
            type: 'bar',
            types: {
                line1: 'line',
                line2: 'line'
            },
            groups: [
                ['data2', 'data3'],
            ],
            names: {
                line1: 'Limit for data1',
                line2: 'Limit for data2 + data3',
                data1: 'Data1',
                data2: 'Data2',
                data3: 'Data3'
            },

        },
        bar: {
            width: {
                ratio: 0.50 // this makes bar width 50% of length between ticks
            }
        },
        point: {
            r: 8
        },

        axis: {
            x: {
                type: 'timeseries',
                tick: {
                    format: '%d-%m-%Y'
                }
            },
            y: {
                label: { // ADD
                    text: '',
                    position: 'outer-middle'
                }
            },
        }
    };

var date1 = new Date(2016, 1, 1, 0, 0, 0, 0);
var date2 = new Date(2016, 3, 1, 0, 0, 0, 0);
var date3 = new Date(2016, 6, 1, 0, 0, 0, 0);
var xAxis = ['Dates',date1,date2,date3];
var line1 = ['line1', 50, 70,80];
var data1 = ['data1', 30, 40, 60];
var line2 = ['line2', 70, 60,40];
var data2 = ['data2',10,15,20];
var data3 = ['data3',15,30,5];
chartSettings.data.columns = [xAxis,
            line1,
            line2,
            data1,
            data2,
            data3];
c3.generate(chartSettings);

 
#chart .c3-line-line1 {
    stroke-width: 0px;
}

#chart .c3-line-line2 {
    stroke-width: 0px;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.4.11/d3.min.js"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/c3/0.4.11/c3.min.js"></script>
<div id="chart"/>    

Answer 1

It would be nice if you attached some jsfiddle.
But at this point I can say that you probably need to look inside .c3-chart-lines container and find desired line eighter by order:

.c3-chart-line:first-child  // or last-child?

or by data name:

.c3-chart-line.c3-target-YOUR-ORANGE-DATA-NAME

Hope this helps.