Data type: PtypBoolean ([MS-OXCDATA] section 2.11.1)

The PidTagAddressBookHierarchicalIsHierarchicalGroup property<43> ([MS-OXPROPS] section 2.531) contains TRUE (0x01) if the distribution list represents a departmental group. Members of this departmental group that are also distribution lists with the PidTagAddressBookHierarchicalIsHierarchicalGroup property set to TRUE represent the child department of this departmental group in a hierarchy of departments. Other members represent members of this departmental group. If the distribution list is not a departmental group, the PidTagAddressBookHierarchicalIsHierarchicalGroup property can be either FALSE (0x00) or absent.