Site to site using OpenVPN with multiple sites

[penley]

Is it possible on OPNsense to use one OpenVPN server to multiple sites in a site to site VPN, if the server uses port 1194 then can all other sites connect in using that same port?

For example we'd like our setup to be:
- Site A: The main site
- Sites B, C, and D are in other regions and need to connect back to Site A.

Sites B, C and D have no need to talk to each other.

I'm struggling to find an answer to this on the internet forums and youtube. I did find the following:
https://forum.opnsense.org/index.php?topic=5675.0 and it seemed to be what I was looking for except on one comment it says "works fine with pre shared key" and then said they ended up creating a server for each site.

Edit:
Based off this conversation https://forum.netgate.com/topic/83777/openvpn-multiple-site-to-multisites-routing/13, it looks like you would have to have multiple VPN servers on the main site A firewall to connect each site.
If this is true would it be that if each site was using the same VPN server and coming in on the same port they'd be competing for the same connection?

Kind regards,
penley