How can I use NetBricks to receive packages on one phy port and send to another port?

I am new for rust , when I run netbricks test cases, these cases are just receive and send on the same phy port. But I have tow phy ports, I want to receive packages on one phy port and send these packages out from the other phy port. just like the real router or NAT do. Can NetBricks do this? Can you gave me one example? Thanks！