Is it possible to associate a VPN tunnel with a domain name, so that when accessing the domain name, we are redirected to the desired tunnel?

Question

VPN

Is it possible to associate a VPN tunnel with a domain name, so that when accessing the domain name, we are redirected to the desired tunnel on all ports?
Idea such:
The VPN server is created, users are got.
For example user1, user2, user3
we get three independent tunnels.
The VPN server has an external address and the sitename.ru domain corresponds to it.
Is it possible to access this server:
user1.sitename.ru:35876 (abstract port) and get into the tunnel corresponding to the first user on port 35876
user2.sitename.ru:35876 and get into tunnel corresponding to the second user on port 35876
Ready to answer clarifying questions.
TK wrote in his own words. Perhaps something is written incorrectly.

Answer 1

umm. domain = IP address. a request like "ip - domain" is made to the dns server. what's with the tunnel? if we are talking about a reverse proxy server that, when accessed by a domain name, automatically transfers all ports to the desired machine ... then yes. there is such. but what does vpn have to do with it?)))
en.wikipedia.org/wiki/%D0%9E%D0%B1%D1%80%D0%B0%D1%...

Answer 2

Let's tell the problem.
There are three working computers. Territorially dispersed. Internet connected. No external IP.
The future server (vpn as I assume) is in the fourth place. Has an external IP.
The task is to get access through this computer (on all ports) to these three working computers.
Its task is very similar to the task of a reverse proxy to forward requests.
But we have this server and working computers are not on the same network, it is possible that we need to access different working computers on the same port. (the option of changing ports on working computers does not suit us)
For the "working computer-server" connection, it was supposed to use a tunnel.
And to separate the tunnels (so that you can use the same ports), use domain names.
Repeating the example: When accessing user1.sitename.ru:35876 (abstract port) and getting into the tunnel corresponding to the first user (the first working machine) on port 35876