#Get all nodes under the current selection
ChildSOPs = []
for node in hou.selectedNodes():
    for child in node.allSubChildren():
        ChildSOPs.append(child)
        
#Make a list of unique types
seen = set()
UniqueSOPs = []
UniqueSOPsSorted = []
for SOP in ChildSOPs:
    if SOP.type().name() not in seen:
        UniqueSOPs.append(str(SOP.type().name()))
        seen.add(SOP.type().name())

#Added this to allow Object Level nodes to be selected
SelectedNodes = []
for node in hou.selectedNodes():
    SelectedNodes.append(node)
    if node.type().name() not in seen:      
        UniqueSOPs.append(str(node.type().name()))
        seen.add(node.type().name())

#Choose the node type you want to edit
UniqueSOPsSorted = sorted(UniqueSOPs,key=str.lower)
input = hou.ui.selectFromList(UniqueSOPsSorted, message="Select Node Type!")
if (len(input) == 0):
    print "Cancelled"
else:        
    #Multi Select the nodes!
    for SOP in ChildSOPs:
        if (UniqueSOPsSorted[input[0]] == SOP.type().name()):
            SOP.setSelected(True,False)
    for OBJ in SelectedNodes:
        if (UniqueSOPsSorted[input[0]] == OBJ.type().name()):
            OBJ.setSelected(True,False)