IP addresses of payment processor nodes

Are nodes of merchant payment processors listed somewhere, so we could pre-seed clients to broadcast transactions directly to the processors?

Here is the problem: when buying something with Bitcoin, usually a payment processor such as Coinbase or Bitpay is in play, and you get 15 minutes to initiate the transaction.

What I experienced today, is that even though I could see an unconfirmed transaction on blockchain.info, Coinbase failed to see it, and the 15 minute timer kept on going. Eventually the payment window timed out.

So, how does one keep this from happening?

Please note: confirmation time is not a problem here, Coinbase in particular allows up to 24 hours for confirmation to occur.

The problem is that Coinbase does not always see unconfirmed transactions.

So, would configuring a client to broadcast transactions directly to Coinbase (in this example) nodes help? And if so, how to learn the nodes IP addresses?

Thanks.