Driving from Mexico to Belize and Guatemala
 

Hi

I am planning to fly into Mexico City, hire car and drive to south. I planning 16 days for this trip. I also want to drive to Belize and Guatemala. But here is my question,
What is the name or names of companies that allow their cars to cross the border to Belize and Guatemala?
I already wrote message to America Car Rental and Mex Renta Car. From Mex i received respond and they don't allow to cross border with their cars.

Is anyone can help?