Hi Kristian,
I have used group layers :
/ADD TRANSPORTATION NETWORK GROUP LAYER
var transportationNetworkGroupLayer = new GroupLayer({
title: "Transportation Network", visible: true, visibilityMode: "independent", layers: [otherRoadsLayer, townRoadsLayer, classCRoadsLayer, classBRoadsLayer, classARoadsLayer, highwayLayer, railwayLinesLayer] });
map.add(transportationNetworkGroupLayer);
However, there are still alot of layers to show in one layerList. The thought was to have multiple layerlists for easier access and aesthetics.