neighbour discovery and more than one NIC

Hi all,

I have a computer set-up that consists of several PC's that are chained 
together. Every PC has two NICs and they are chained like this:
PCA (eth 1) <---> (eth2) PCB (eth1) <--> (eth2) PCC (eth1)

All the addresses run Neighbour Discovery. Now suppose I want to connect 
to the address corresponding with eth2 on PCC from PCA. When I try to 
ping it, the ping request gets to PCB but then blocks (PCB doesn't 
forward the request to PCC via eth1), I suppose this happens because it 
has to "switch" from NIC.
Is there a way to ensure that this connection can be made with Neighbour 
Discovery? So in other words that I can connect two subnetworks with the 
two NICS?

Thanks in advance for your help!

Steven