when walking through the portal you are randomly teleported to an x and z coordinate with added implementation of working with plugins such as GriefPrevention, Towny, World Border, World Guard, etc.

For now, I have created basically plugin that can run command when entering portal: https://www.spigotmc.org/resources/multiverse-commanddestination.90232/

You can just get a random teleport plugin and config it to run the relevant commands.