Graylog Alert with multiple messages in one mail

Hello

In my current setup i get an email for every event with one single message.
Would it be possible to get one mail with all messages found matching the filter criteria?

In the filter & aggreagation setup i search for a query within the last 24 hours and execute the seach also every 24 hours.
The filter preview shows me 4 messages found.
In the notification tab i have set backlog to 50 messages.
Shouldnt the backlog feature iterate through all events found and include all messages in the mail?

This is myTemplate:
— [Event Definition] ---------------------------
Title: {event_definition_title} Description: {event_definition_description}
Type: {event_definition_type} --- [Event] -------------------------------------- Timestamp: {event.timestamp}
Message: {event.message} Source: {event.source}
Key: {event.key} Priority: {event.priority}
Alert: {event.alert} Timestamp Processing: {event.timestamp}
Timerange Start: {event.timerange_start} Timerange End: {event.timerange_end}
Fields:
{foreach event.fields field} {field.key}: {field.value} {end}
{if backlog} --- [Backlog] ------------------------------------ Last messages accounting for this alert: {foreach backlog message}
{message} {end}
${end}

Running Graylog 3.1.2