Trigger on Incoming Review Based on Criteria

We would like a trigger to fire based on a 1 to 3 start review received from the guests.  This will alert us that there is a issue with the condo and may be resolved before a 1-3 start review is received again.  

This is badly needed and one of the functions I miss from my old PMS.  I want to run a trigger based on a 5 star review, but no review triggers are available as best I can figure.