client and server with different ports

Hi,
I'm developing a multiplayer game with dedicated servers.
The dedicated servers should run with same IP and different ports.
But now Im afraid of the connection between clients and servers, if the client has an other process active on a port that it should connect to.

Can i do easily sth like:
All clients listen on "global" port and servers listen on their specific port.
Clients send data to the server IP with specific server port and servers send data to "global" port and specific...

client and server with different ports