MySQL Replication Between Three Hosts?
It is feasible (you can chain-replicate more than 2 servers), but unnecessary: you can forward access using a VPN or, if you do not want to set that up, with simple SSH port forwarding. 

This applies even if you have a Windows server -you can install OpenSSH or any other SSH software or application that allows you to forward ports. SSH is the standard secure tool on unix.