The way you can accomplish this now would be with multiple alerting profiles and likely 2 custom events for alerting. There's no concept of different severity thresholds on a single event/metric.
One alerting profile would make use of the 'warning' custom event for alerting through the it's filters (probably would want to use the custom event filters at the bottom to use just your 'warning' event). The second alerting profile would be tied to a different 'severe' custom event for alerting i.e. the same type of event as in the first step just with a higher threshold).
Then the first alert profile can be used with an email notification and the second could be used with the severe event and the SNOW integration.
If just the warning event occurred only the first alerting profile would match and only an email would be sent. If it violated the severe threshold then the second alerting profile would match and a SNOW problem notification would be triggered.
https://www.dynatrace.com/support/help/shortlink/alerting-profiles#create-an-alerting-profile
https://www.dynatrace.com/support/help/how-to-use-dynatrace/problem-detection-and-analysis/problem-d...
