Just an Explore/Correlate would not result in a notification for which you could trigger a PX Policy on. If running an Update as part of the Explore/Correlate then that may result in a modify of the Provisioning Global User (depending on if there were any Endpoint Attribute Mappings involved.
If there was such a modify of the Provisioning Global User then there would be a Modify_Global_User inbound notification which would get sent to the IM Server and would trigger a Provisioning Modify User task. You could then have PX Policy configured to run on that task where that PX Policy could try looking up the associated AD Account data and then take an action based on that.
Now with all the above said, I am not sure if this is really the best approach as it may not be the most efficient. You may be better off with an out of band process that dumps data locally on the domain controller side and scrapes the data to determine what changes to apply and then submit those changes.