Merge shapes using axlShapeMerge

Hi

 Please give me anyone's advice...

1. Using below code, I expect only shapes in some layer can be picked in obj, but obj contains shapes in all layers. Is it normal??

  axlSetFindFilter(?enabled "shapes" ?onButtons "shapes")
  axlVisibleDesign(nil)
  axlVisibleLayer("some layer" t) 
  axlSingleSelectBox()
  obj=axlGetSelSet()

 2. Certain layer is filled with many of shapes, How can I merge each other.. I'd like to merge all shapes, if they are connected each other.

 - I tried below code to do.. but it took too much time and not that successful.. since when I use 'axlShapeMerge(a b nil)', members of list b should be connected to a.. unless return error and skip this function... 

 allShapes = getAllshapes(some layer)
 foreach(shape allShapes
  when(shape->bBox
   axlClearSelSet()
   axlSingleSelectBox(shape->bBox)
   slist=axlGetSelSet()
   foreach(s slist
     when(axlShapeMerge(shape s 'check) shape = axlShapeMerge(shape s 'quiet) )
    ) 
  )
 )