Unfortunately I don’t believe you’ll be able to do this in the manner you are suggesting. The Alarm.com skill for Alexa allows you to manually trigger a recording by voice, but camera triggered activity is not supported afaik.
You can set up similar rules in Alarm.com analytics however with Z-wave lights connected to your alarm panel. Alarm.com motion analytics rules can trigger specific Z-wave lights. Analytics is supported on the Protect and Complete plans with certain camera models. Read more here.