opendap/src/main/java/ucar/nc2/dods/DODSNetcdfFile.java
private boolean isGroup(DStructure dstruct) {
    BaseType parent = (BaseType) dstruct.getParent();
    if (parent == null) return true;
    if (parent instanceof DStructure)
      return isGroup((DStructure) parent);
    return true;
  }
private boolean isGroup(DStructure dstruct) {
    BaseType parent = (BaseType) dstruct.getParent();
    if (parent == null) return true;
    if (parent instanceof DStructure)
      return isGroup((DStructure) parent);
    return true;
  }
make a structure into a group if its scalar and all parents are groups