public string GetGroupInfoListByDepartment(string departmentID, bool recursive)
    {
        if (!header.VerifyCredentials(header.UserName, header.Password, header.Type))
        {
            return(string.Empty);
        }

        Guid gDepartmentID = (Guid)XmlSerializer.Deserialize(departmentID);

        return(XmlSerializer.Serialize(OrganizationPublicHelper.GetGroupInfoListByDepartment(gDepartmentID, recursive)));
    }