{{ range $host, $containers := groupBy $ "Env.VIRTUAL_HOST" }}
upstream {{ $host }} {

{{ range $index, $value := $containers }}
    {{ with $address := index $value.Addresses 0 }}
    server {{ $value.Hostname }}:{{ $address.Port }};
    {{ end }}
{{ end }}

}

# конфигурация веб-сервера
server {
    listen 80;

    location / {
        proxy_pass http://{{ $host }};
    }
}
{{ end }}