Multiple Docker Hosts?

[RickBankers]

This is an awesome setup!
I have 3 separate docker hosts and have the agents running on 2 of them and prometheus, grafana, etc running on one. I can see the grafana dashboard for the local host however I don't see the remote docker hosts. I did read the note describing external labels but I have no idea how to get it to work. What I'd like to see is the hostname in the container name and host metrics dashboards so I can tell where the container or host I am looking at.