The same SSH tunnel for multiple hosts

I am super new in SSH and I want to create an SSH tunnel that resends several ports. Let's say I have three hosts instead of forwarding ports like A-> B-> C, I should be able to connect any of these servers.

Imagine master-slave and A is master where B and C are slaves. If A goes down, I want to connect to B or C. So it will not be like a serial connection like A-> B-> C, it's a parallel connection.