Hello,
We usually discourage having one Stripe account for 2 separate websites as they are often for different business lines and should be separated into their own Stripe accounts.
Otherwise, there isn't a way to do what you are after as this is not how our Webhooks work today. All webhook endpoints will get all those events and it isn't "per transaction" if that makes sense. So if you create a payment for $100 from site A, it will create a `payment_intent.succeeded` event and that event will be sent to both your webhook endpoints if they are listening for it.
What you can do is use metadata [1] to store information about which website processed that payment. Then on your 2 webhook endpoints, you can write code to ignore events with metadata associated with the other website.
While this works, this won't scale if you add more websites since you can not create an unlimited number of webhook endpoints. But it might be enough if you only have 2 websites.
Hope this helps!
Remi