Port forwarding between 3 dedicated servers

I have a main node on one dedicated server where all ports are opened. I have to additional dedicated servers where some ports that we are using to communicate between servers are closed by ISP provider. So, I can not establish a connection between them using the internet IP address of the main server. I have created SSH port forwarding from one of the dedicated servers with closed ports using a command like that: ssh -fNT -L 84xx:localhost:84xx user@main_server_IP It works when I have only one port forwarding but how to make that for 2 and more servers with closed ports? Also, I think localhost is not correct usage when I have more than one servers for forwarding connection. How I can create an Intranet address apart from a static IP address that each server have? Or I can use a static IP address instead of localhost? I need to forward only communication that node establishing via 84xx port all other connections should go in the regular way without a tunnel.