Can you add a condition to the AI that it only opens the L-Sector if it possesses adequate fleet power?

My last game was nice and challenging until an AI opened to L-Sector and the Grey Tempest cleared out half of the galaxy, including artisans, curators, ... I was secluded and turtled up 'till I got enough fleet power to clear the L-Sector.

Now four of the AIs are gone and the others are "pathetic" in relative power.