Here are my suggestions for you:
1. If you want to connect an actual Serial Terminal to multiple hosts
the easiest thing to use is a DB-9 or DB-25 switch box. Something like
this:
https://www.amazon.com/Kentek-Female-Peripherals-Devices-Printer/dp/B07KWTJ…
2. If you want to be able to connect to multiple serial host over your
LAN one option would be to use any number of a myriad of multiple serial
port to USB adapters. Something like that:
https://www.amazon.com/Gearmo-Serial-Windows-Certified-Drivers/dp/B004ETDC8…
Then you can VNC or RDP (Remote Desktop) into the PC and then
connect to the serial ports with a terminal emulator.
However, that does not allow you to use your serial terminal.
3. If you don't want to run RS-232 cables to your hosts you can use
this to connect them to your network using something like this:
https://www.amazon.com/CERRXIAN-Ethernet-Serial-Device-Converter/dp/B087J9F…
You connect to your hosts with any TCP/IP capable terminal emulator.
However, that does not allow you to use your serial terminal.
Good luck.