Can a local Ubuntu mirror host different Ubuntu releases on a single server

I am interested to know if I have a Ubuntu 20.04.3 LTS server, can use it as a local mirror to host 20.04.3 LTS and 18.04.6 LTS repositories, such that my 18.04 servers can pull from it as well as my 20.04 servers? Or, do I need 2 separate servers, one on version 18.04 and the other on 20.04?

Is there a best practice design on how to set this up?

The same mirror can host two or more repositories. Check out http://mirrors.edge.kernel.org/ubuntu/ and poke around the directories to get a better idea of how this works.

The package list downloaded by apt indicates which package version is needed for each release. All the different package versions are located in the same directories.