Zabbix Trapper configuration for multi_value in Logstash

[singu]

Hi,
I am trying to configure multi_value in my logstash configuration for zabbix and not sure what should I configure "Key" in the Zabbix UI. Without multi_vaue, i was able to configure "zabbix_key" in the Zabbix UI. With multi_value, what would be the "Key" in Zabbix UI.

Thanks in advance

Thanks,
Singaiah