Group multile messages into one

Is there way to concat messages into one ?

i have about 500 hosts and need to check its heartbeat. If it fails it should notify me or my team in slack. Normally I`d use a groupBy(host) and send alert if something wrong, but if (for example) I got 100 filing hosts - Ill get 100 messages, which is unreadable.

Hi , maybe a bit late but this might help …

Best regards,