Okay if I'm reading this it's because you want to ssh into two or more servers from the outside. I get the goal, but I'll tell you it's not great security.
What I personally have used and recommend is that you set up a bastion ssh server. A public ssh server that is exposed, preferably on another port, that is heavily locked down. Once you ssh into the bastion, then you're in the network and can ssh anywhere using your internal DNS.
The added security benefit is that if someone does get into that box, they still need to learn your network topography. Not security, but bastion doesn't do anything, so they're not immediately into a core system.
Added bonus if you do a honepot on 22 and bastion on a different port.