I have a webmap that displays the contents of a dynamic map service. For performance reasons I'm currently using FeatureLayers for the individual sublayers (they are all point layers with relatively few features).

However, this makes them show up in the legend as individual items, e.g.:

• Layer 1
• Layer 2
• Layer 3
• Layer 4
• Layer 5

when I'd like to group them as they are in the original service:

• Group 1
  • Layer 1
  • Layer 2
• Group 2
  • Layer 3
• Group 3
  • Layer 4
  • Layer 5

Is there a way to load a whole service as with DynamicMapServiceLayer, but use FeatureLayer rendering for the sublayers?