creo4 config.pro option documentation for: IGES_IN_GROUP_TO_DWG_LAYER 
iges_in_group_to_dwg_layer
yes
, no
*
Determines the conversion of an IGES group to drawing layers. This configuration option is available as Import Groups As Layers
in the Import IGES
dialog box.
yes
- Converts an IGES group to drawing layers.
no
- Does not convert the IGES group to drawing layers.