I am also facing same problem. I have defined one custom event for alerting on a service for response time monitoring. But whenever it trigger, it also send notification to all other alerting profile because it has some common tags. What I tried to do it to use Add a event filter in all remaining alerting profile which I want to ignore. For that I deined like -> "Custom: Title not contains 'Americas US [Microservice] subscriptions [P2 QA]'" . But that did not work for me. There are only two options comes in drop down :- custom and predefine and both are useless for me, it seems.
Please suggestion what should I do now. I don't want management-zone related solution. I want a small fix for small problem like this.