First off, I'll give you the network setup.
(modem's IP is 173.163.40.X)
The main router that connects to the modem has an IP of 172.16.1.1 (This is RTR A)
The next in line has an IP of 172.16.69.69 (RTR B)
and the final router has an IP of 172.16.16.69 (RTR C)
the subnet is setup as 255.255.255.0

Now here is the question, Is it possible to get RTR C to forward the port 11075 from the modem connection to the PC's IP of 172.16.16.85 without involving the setiings of RTR A and RTR B.
Or do I have to set each router to forward the port from one to the other in sequence.
If that's so, I don't have access to my neighbor's router (RTR A) and he refuses to forward ports because "it's way too risky".

It would be nice to get that one port forwarded so I can host a Terraria server without paying the full price of high-speed internet (3 Megabytes per second) (Me and my neighbor pay half and half so that it isn't so taxing on either side).