How do I direct SOCKS5 proxy traffic to other SOCKS5 proxies based on ports?

If you can help point me in the right direction, it would be appreciated.

So I bought a bunch of premade SOCKS5 proxies from a provider, and I want to set up a single Linode VPS as a SOCKS5 proxy that can point to other proxies depending on the port.

This is my Linode server's IP address: xx.xxx.xx.xxx


I want socks5 connections to particular ports to be redirected to the socks5 proxies I bought.


For example, this way (randomly generated IP addresses for forwarded destination):
xx.xxx.xx.xxx:8000 -> 67.229.232.91:1080

xx.xxx.xx.xxx:8001 -> 2.80.200.206:1080

xx.xxx.xx.xxx:8002 -> 43.14.235.96:1080

xx.xxx.xx.xxx:8003 -> 114.232.168.4:1080

xx.xxx.xx.xxx:8004 -> 84.12.192.10:1080 and so on.

So for example, if I went on Proxifier on Windows:

if I connect to xx.xxx.xx.xxx:8001, i'd get 2.80.200.206 on whatsmyip.com.

if I connect to xx.xxx.xx.xxx:8003, i'd get 114.232.168.4 on whatsmyip.com.

The point of this is to make proxy management easier for my use case.
I have a lot of proxies that I need to replace in a tedious GUI on a Windows software.
It gets hard to manage, so my end goal is to have a setup like this,
in a way that I can have a simple text file in the format:

xx.xxx.xx.xxx:8000-> proxy1:port

xx.xxx.xx.xxx:8001-> proxy2:port

xx.xxx.xx.xxx:8003-> proxy3:port, etc.

This way, I'd set up that static ip on the GUI software, only once and don't touch it again. I want to have a central proxy list text file to deal with this in one place. To do any replacements, I'd go edit my text file.

xx.xxx.xx.xxx:8001

xx.xxx.xx.xxx:8002

xx.xxx.xx.xxx:8003 etc.


Eventually I could make it be a web database, but that's finishing touches. Ideally, replacing any proxy in this file would not make other connections be disconnected.


So I assume I'll have to write a program for this part, to keep each connection isolated from each other, unless there's something already made.


It seems like a very simple concept though, I would be surprised if nothing already exists in open source for this.

I see proxy companies sell "backconnect" SOCKS5 proxies, which is this exact same setup. 
But no results on how they accomplish this, and the fact that I need SOCKS5 makes it harder to find relevant results.


Also, the proxies I buy are premade, so you can only access them as SOCKS5 proxy.
They don't allow SSH access so I can't go into each server and install additional software.


Please, let me know if you happen to know any information on this/what tools to research.

Thank you