In many cases, when a particular "served" port is used, that port doesn't actually carry the real traffic. It is at most a gate-keeper to the resources behind it. It is like a receptionist asking "how may I direct your call?" TCP/IP-based connection protocols listen on that port on the server. A prospective client sends the connection request to, say, port 8080, seeking a web connection (because that is what port 8080 usually does). Even with UDP-based protocols like HTTP, it still works this way.
A pool (or range, if you prefer) of port numbers is available to the server-side connection. So if the type of transaction will require bulk data exchanges, the network layer will "unclog" the target port. To do so, it PICKS one and sends back that port number to the client's address and port - BOTH of which were identified in the original message header sent to the target port. This is called port negotiation and is an automatic feature of most TCP/IP-based client/server protocols. It is possible that the return message from server to client might request a negotiated port for any bidirectional exchanges later. Many protocols do that.
Therefore, the answer to your "can they all communicate" is "probably yes - particularly if the firewall is prepared for TCP/IP port negotiation. If EVERY system is using port 8080, they will still have an IP address AND a port number in the message header, so even without port negotiation, they can still talk to each other and keep the exchanges straight.
The fact that a server is virtual has no practical meaning here because virtual servers usually have their own "private" IP address and will listen for that address, not the physical address on the hardware network card. That's the fun of TCP/IP over Ethernet - you can listen to anything. That's why there was a product called "Sniffer" that could monitor Ethernet network traffic and snag whatever was passing by. The fact that you are looking at a web server means it will correctly handle the protocol setup to allow a thousand different connections if needed (and if licensed for it).
If I misunderstood something in your question, please clarify, but as I read it, I don't see a problem.
