2 Logstash for load balancing and avoid duplication

Till now I was using only 1 server with logstash for sending syslog data to Elasticsearch. I am switching to 2 servers with logstash for load balancing and using f5 VIP, is there a way logstash from different instances can send the same data to Elasticsearch without duplicating in Elasticsearch?

The F5 will load-balance connection requests between the two instances. Any data sent to the F5 will only get sent to one of the logstash servers, so there will be no duplication.