Yes, there is a way to tunnel through. To explain, lets assume the following layout with one chassis with two Ethernet adapters, and another chassis with one adapter:
Your computer: 192.168.1.230
PLC Chassis #1 Enet Slot #1: 192.168.1.20
PLC Chassis #1 Enet Slot #2: 10.10.10.50
PLC Chassis #2 Enet Slot #0: 10.10.10.60
In RSLinx, when you browse your EtherNet/IP driver we will assume you will see Chassis #1, but you cannot see Chassis #2.
If you were to browse to Chassis #1 and view the modules connected to the backplane you would see both Ethernet modules. If you clicked on the "+" next to the module in slot #2 you would see an Ethernet network and if you clicked on the "+" it would not discover the other chassis. But, it can.
You can manually enter in the IP addresses of Chassis #2 Ethernet module. I don't have a live system here that I can walk through, but if you right-click on that Ethernet network and it may be the "Properties" option that gives you the ability to manually enter an IP address (or multiple address).
So by manually entering this information you can now browse and view that other network. Once you browse to Chassis #2 and see the backplane you can right-click on the backplane and create a Shortcut. Give it a name like "Chassis_2" (you can pick a better name) and you will now see that listed as if it were a separate driver just like your EtherNet/IP driver. You won't have to manually tunnel through those modules to get to that remote chassis.
So lets call this tunneling to one level deep. While I have not tried tunneling two levels deep or further, it should be possible.
Note though......this configuration is stored in your copy of RSLinx only. Someone with a different PC will not see this without going through all those settings again manually. I have not tested the RSLinx Backup Tool to see if it saves this configuration. I know at the time I tried it did not save the shortcuts.
The PLC systems also cannot make use of this. You would have to follow Ken's post to get the PLC to be able to do this.
Good luck!
OG