Access SAP Server remotely using SAP GUI

Hello,

I made two different SAP ECC6 EHP6 IDES installations in two systems of my personal LAN at home using WIFI.

I then used dynDNS to point out on my public IP address.

I also opened the necessary ports for the two PCs (192.168.1.5 and 192.168.1.6) on the router.

Now the problem is in SAP GUI, I can access only to one of the two systems remotely even if fill the System ID field with the other value, I'm always connected to the same system and I don't know why.

Please help me find a solution to this problem.

Thanks in advance.