[OpenLayers-Users] Grouping Layers

[Bill Thoen]

I've got some NAIP imagery split into tiled layers, each with a 
different resolution appropriate for the scale at which they should be 
displayed. But what I'd like is to have these layers appear as one layer 
on the LayerSwitcher list, and preferably in the base map section. Since 
I'm using MapServer to build the images I tried using the GROUP 
directive to combine the multiple layers into one while using different 
scales so that only one of those layers would be visible at a time. 
Also, all my sub-layers are tile indexes (but I don't think that should 
matter.) While I think this technique works in MapServer, when I try it 
in OL, I get only then top layer in the group. None of the other layers 
appear at any scale. Here's what I'm doing in my mapfile:
   LAYER
      NAME "naip6"
      GROUP "naip"
      TYPE RASTER
      DATA naip/naip_0000_6.tif
      STATUS ON
      MINSCALEDENOM 100000
   END

   LAYER
      NAME "naip0"
      GROUP "naip"
      TYPE RASTER
      TILEINDEX "naip0"
      TILEITEM "location"
      STATUS ON
      MAXSCALEDENOM 99999
   END

This layer is being loaded into OL as a WMS layer with the name 'naip'. 
Is this the right approach for creating a multi-zoom layer or can I even 
do something like this with OpenLayers?

Thx,
- Bill Thoen