PCAP replay

I am looking for programs to replay pcaps.

tcpreplay is not working well for me.

My setup:

Machine 1 ---- GW ---- Machine 2 | My Computer 

I want to send all the pcap packets from Machine 1(which is 'attacker') to Machine 2 (which is 'attackee')

tcpreplay doesn't send to spesific ip (which I need to catch traffic in GW)

I tried using it but the GW doesn't see the traffic. (because the attacker should send to spesific IP and not 'broadcast' the packets - the GW watches for traffic for both of them)

Any suggestions? I prefer Python scripts.