grouped arc chords

<!DOCTYPE html>
<head>
<meta charset="utf-8">
<script src="https://d3js.org/d3.v4.min.js"></script>
<script src="d3-chord2.js"></script>
<style>
body { 
 margin:0; position:fixed; top:0; right:0; bottom:0; left:0; }
</style>
</head>
<body>
<script>
  
var m1 = [[0,0,0,0,0,0,0,0,0,2.58],[0,0,14.97,0,0.45,0,0.76,0,0,0],[0,14.97,0,0,0,0,0,2.26,0,0],[0,0,0,0,0.08,0,0,0,14.54,0],[0,0.45,0,0.08,0,0,0,0,0,0],[0,0,0,0,0,0,0.69,0,5.11,0],[0,0.76,0,0,0,0.69,0,0,0,1.98],[0,0,2.26,0,0,0,0,0,0,0],[0,0,0,14.54,0,5.11,0,0,0,0],[2.58,0,0,0,0,0,1.98,0,0,0]];
var sectors = [
    [0, 1],
    [2, 3],
    [4, 5],
    [6, 7],
    [8, 9]
]
var width = 300,
  height = 400,
  outerRadius = Math.min(width, height) * 0.5 - 35,
  innerRadius = outerRadius - 20;

var svg = d3.select("body").append("svg")
  	.attr("width", width)
  	.attr("height", height);

var chord = d3.chord2()
    .padAngle(0.35)
    .arcGroups(sectors)
    .sortArcGroups(d3.ascending)
    .sortSubgroups(d3.descending)

var arc = d3.arc()
    .innerRadius(innerRadius)
    .outerRadius(outerRadius);

var ribbon = d3.ribbon()
    .radius(innerRadius)
  
var color = d3.scaleOrdinal()
    .domain(d3.range(2))
    .range(["steelblue", "#b1b5b7"]);

var g = svg.append("g")
    .attr("transform", "translate(" + width / 2 + "," + height / 2 + ")")
    .datum(chord(m1));

var group = g.append("g")
  .attr("class", "groups")
  .selectAll("g")
  .data(function(d) { return d.groups; })
  .enter().append("g");

group.append("path")
    .style("fill", function(d) { return color(d.index); })
    .style("stroke", "black")
    .attr("opacity", 0.4)
    .attr("d", arc);
  
  g.append("g")
  .attr("class", "ribbons")
  .selectAll("path")
  .data(function(d) {return d; })
  .enter().append("path")
  .attr("d", ribbon)
  .style("opacity", 0.4)
  .style("fill", 'gray')
  .style("stroke", "black")
  .on('mouseover', function(){
      d3.select(this).style('opacity', 0.9)
  })
  .on('mouseout', function(){
      d3.select(this).style('opacity', 0.4)
  })

</script>
</body>

https://d3js.org/d3.v4.min.js