Hello sir,
Let me explain how I'll implement that script. Firstly, It will use tcpdump to calculate number of packets. So, you should run script for a few seconds and then it will give you a result. You also may use iptables rules to count packets. (Tell me if you wish.) Secondly, you should provide list of IP addresses of your VM's. Then script filter inbound traffic and sums number of packets for each IP.
I can implement it in a few hours. I provide you fully commented script and answer for any question you have.
Best,
Vyacheslav