As stuartwhyte mentionned, you would need to use the Trap Viewer instead of the Advanced alert Manager.
Once in Trap Viewer, go to View - Alerts/Filter Rules
In the Alerts/Filter Rules Tab, click Add new rule, and go to the Trap Details Tab. Fill in the text you are looking to match in the Trap Details pattern:
If you have multiple devices that can send the same text string, you can also set-up a trap rule:
Since in the trap viewer there are no reset conditions, you will need to create another rule for the "Alarm OFF" traps.
Hopefully, this should address the mentioned need.