Allow users to group layers and sublayers within the layer list widget so that layer groups can be expanded and collapsed.
The current way would be to publish a map service which allows layer grouping, then add the map server to the web map. However; we are working with individual image services. By adding them to the web map as image services, we can configure the pop up for each image service and retrieve pixel values in the web app.
If we are to publish a map service with these raster layers and add the map service to a web map, we can no longer enable pop ups for the individual image service/raster layers to retrieve pixel values on map click events.
The web map object (this.operayerInfos) does not seem to have a method to remove and add layers to itself inside the layer list widget.js in order to place separate groups of layers in separate div elements within the layer list widget html. It seems to be an all or nothing, add all layers to this div or add all layers to this div.
I'm not an expert but all support analysts tell me this functionality is not supported.