Um agente do Datadog respondeu à minha pergunta em sua página da base de conhecimento: link
Alexis Lê-Quôc
DEC 30, 2013 06:58AM EST
Datadog Agent
You can indeed do that with “Multi-alerts”, basically creating one alert that’s going to apply to all the hosts that share the same tags. Here’s a more detailed guide to alerting: http://docs.datadoghq.com/guides/alerting/