protected function getLdapFilterForAliases()
    {
        $filters = [];

        foreach (array_keys($this->aliases) as $alias) {
            $filters[] = $this->getLdapFilter($alias);
        }

        if (count($filters) == 1) {
            return $filters[0];
        } else {
            return bOr::SEPARATOR_START.bOr::SYMBOL.implode('', $filters).bOr::SEPARATOR_END;
        }
    }