Public Global IP allowing connections through identical address

This might be a simple answers, or maybe something that doesnt exist yet. I was thinking about decentralization and how 2 computers could connect to each other without knowing the others address. I wanted to know if there was a global address that computers could connect to based on maybe a special identifier. For example, if both computers were connected to this global IP and searching ford the address 12345... Maybe they could connect through something like that.

Does this exist? Maybe this is a common sense question.

Thanks!