class \Shared\Department
{
  public const ADMINISTRATION = 1;
    public const SALE = 2;
    public const WEBDEV = 3;
    public const ADV = 4;
}

class \Employee\Department extends Enum
{
    private const ADMINISTRATION = \Shared\Department::ADMINISTRATION;
    private const SALE = \Shared\Department::SALE;
    private const WEBDEV = \Shared\Department::WEBDEV;
    private const ADV = \Shared\Department::ADV;
  
  ... код только для контекста сотрудников ...
}

class \Project\Department extends Enum
{
    private const WEBDEV = \Shared\Department::WEBDEV;
    private const ADV = \Shared\Department::ADV;

  ... код только для контекста проектов ...
}

/**
 * @property-read string $shortname
 * @property-read string $supportProjectTags
 */
class \Project\Department extends Enum
{
    private const WEBDEV = \Shared\Department::WEBDEV;
    private const ADV = \Shared\Department::ADV;

  public static function items()
    {
        return [
            self::WEBDEV => [
                'name' => 'Веб-разработка',
                'shortName' => 'Вебдев',
                'supportProjectTags' => true,
            ],
            self::ADV => [
                'name' => 'Отдел рекламы',
                'shortName' => 'Реклама',
                'supportProjectTags' => false,
            ],
    ];
  }
}