Orion.ActiveAlerts - can I get the "Trigger Action" to run for all Active Alerts?

There is no API for re-firing the trigger actions on alerts, so you will have to build this repopulation capability externally. Here's how I would do it:

1. Modify the existing trigger action that sends the alerts to the central system so that it records its command line in a simple table where the key is the alert identifier (definitionId, objectType, objectId) and the value is the command line for the external program.

2. Add a reset action that removes the table row created in #1.

3. When the centralized system clears itself and needs to be repopulated, you can use this table to rerun these trigger actions for the currently-active alerts.

I would prefer to poll the internal sql table for active alerts... and then automate the refresh based on that.   would that work?

Possibly. I depends what details need to be passed to the other system. If Orion.ActiveAlerts has everything you need, then you can poll it and repopulate the other system based on that. But if you need other information (for example, information that is available in macros you use to build the command line for your tool), then that state will need to be saved somewhere else.