Is it possible to send a complex report with alert requests to ELK?

Question

Automation

Didn't work closely with ELK before, but a question arose.
Suppose there are logs similar to the following (time varies)
2019/10/10 13:10:00 User raised request REQ1030540 (10 ms)
2019/10/10
13:30:00 /10 13:30:00 Assigned task TSK0001 from REQ1030540 (20 ms)
2019/10/10 13:40:00 Completed task TSK001 from REQ1030540 (101010 ms)
2019/10/10 13:40:01 Request completed REQ1030540 (203050 ms)
I put an alert on Request completed if it took longer than 1000 ms, and at the same time I want to receive a report with all the lines that mention this request (in this case, REQ1030540)
Hands povybirat all this is easy, but dreary. Maybe I want to add some fetch thread and information to the email, which should go away when the alert is triggered.
Questions:
Can you run an external program as an alert (a bash script that does everything you need through api?)
Can this be done using a purely ELK stack, or do I need to install something additionally, some thread plugins?
How would you solve such a problem?