How to organize multiple Docker projects with different versions of PHP-Apache?

Question

Docker

How to organize multiple Docker projects with different versions of PHP-Apache? On one, the php:7.2.12-apache image, on the other, the php:5.6-apache image, while they communicate with the servers through port 80. But the second one does not start on the same port, because it is busy. And if you do it on a different port, for example 81, then the site will come off at localhost: 81, but you need to do it without specifying the port. What is the best way to do this?

Answer 1

Run them on different ports and run them through the third one, which uses them as a backend

Answer 2

What's wrong with Apache PHP-FPM or FastCGI?