I have   the elasticsearch destination working correctly, but if I try to use multiple rsources, I get an error

destination d_elasticsearch_0 {
elasticsearch(
    index("flare-${YEAR}.${MONTH}.${DAY}.${HOUR}")
    type("flare")
    cluster("es-dcs-dev")
    client_mode("node")
    flush_limit("10000")
    template("$MESSAGE                    ")
    resource("/etc/elasticsearch/elasticsearch.yml")
);
};

works fine, but if I add a second resource

destination d_elasticsearch_0 {
elasticsearch(
    index("flare-${YEAR}.${MONTH}.${DAY}.${HOUR}")
    type("flare")
    cluster("es-dcs-dev")
    client_mode("node")
    flush_limit("10000")
    template("$MESSAGE                    ")
    resource("/etc/elasticsearch/elasticsearch.yml;/etc/elasticsearch/logging.yml")
);
};

I get an error

Starting system logger (syslog-ng.esgateway): [2016-06-07T09:01:58.694633] org.syslog_ng.elasticsearch_v2.client.ESNodeClient.loadConfigFile:69 - Can't load settings from file, file = '/etc/elasticsearch/elasticsearch.yml /etc/elasticsearch/logging.yml', reason = 'Failed to open stream for url [/etc/elasticsearch/elasticsearch.yml /etc/elasticsearch/logging.yml]';

Can anyone shed some light on how to configure multiple resources?

-- 
Evan