Get child layers from a layer group

Question

I'm using a geoserver and openlayers3 with html. I cannot find the way to obtain the child layers from a layer group. I have a layer group, and I show it in html perfectly, but what I want is to be able to access their children layer, in order to print a checkbox for each one to be able to choose if I want to hide or show each one. I don't know if it's possible, and if so, if I have to make a call using the geoserver to get the layers and then make the call to print them, or it is some method inside openlayer.

The code to print the layer group:

new ol.layer.Group({
    title: 'layer1_group',
    layers: [
      new ol.layer.Tile({
        title: 'layer1_group',
        source: new ol.source.TileWMS({
          url: 'http://testestest:8080/geoserver/geo.test/wms?service=WMS',
          params: {'LAYERS': 'layer_group_3layers'},
          serverType: 'geoserver',
          crossOrigin: null
        })
      })
    ]
  })

layer1_group: contains 3 sub layers. Those three are what I want to print separately.

So now I print only the layer group with the children all together, as the shown image:

And what I want is to print the children separate:

Answer 1

I found the solution.

If you want to get the children layers from a layer group then you have to make a call to the api, like that:

http://your_server/geoserver/your_schema/your_LAYER_GROUP/wms?request=GetCapabilities

So you have to fill in the url with your data, taking care where it puts "your_LAYER_GROUP" to enter your layer group. With this you will have an xml containing a node named as <Layer> and inside it, it will appear N nodes deppending on the number of sub layers that the parent has.

Then to print it dinamically from an html site, using javascript is easy:

var layerNew = new ol.layer.Tile({
        title: 'new ',
        source: new ol.source.TileWMS({
          url: 'http://your_server/geoserver/your_schema/wms?service=WMS',
          params: {'LAYERS': 'THE_LAYER_NAME_THAT_APPEARS_IN_THE_XML'},
          serverType: 'geoserver',
          crossOrigin: null
        }) });

map.addLayer(layerNew)