Create event with multiple entity via v2 API

[william_cher]

How do I create an event via API, where this event consist of multiple entity? 

Im creating event via POST v2/events/ingest, body as follow:

{
  "entitySelector": "type(SERVICE),entityId(SERVICE-A****,SERVICE-B****)",
  "eventType": "CUSTOM_ALERT",
  "title": "TESTING Error",
  "timeout": 5,
  "properties": {
       "dt.event.description": "testing",
      }
}

Problem I have is that Dynatrace will create 2 separate event instead of merging it as one.