Is it possible to split 3000 domains into 3 IPs on NGINX?

Question

Nginx

The current task could not be solved by the 3rd system administrator, so I appeal to the community.
Currently there are 3 hosts and 3000 domains, where every 1000 is delegated to each host.
The server is running NGINX and the problem is that all domains open the page from the first host.
Task: without prescribing each domain in nginx so that the content is given according to the delegated IP

Answer 1

The current task could not be solved by the 3rd system administrator, so I appeal to the community.

I'm afraid this is simply not their qualification since they could not solve such a banal task.
How delegated ip?? Through DNS in sense?
Let the sysadmins read the documentation. This will be enough to configure this virtual host for the current task.
https://nginx.org/ru/docs/http/request_processing.html

Answer 2

There is a variable $server_addr
based on which you can adjust the responses.
For exampleroot /var/www/$server_addr/

Answer 3

Setting the default_server directive to listen
does not help