Gmail email filtering. How to forward only the first email in a chain?

Question

gmail

Letters with exactly the same content and subject are collected in a chain.
How to forward only the first letter of the chain to another address and under no circumstances forward other letters from the chain?
Is this possible with Gmail tools?
If not, what is the easiest way to organize? If you offer another mail service, then it should be reliable, secure and fast.
Thank you.