Check if a user pays another user for bitcoin website I am creating a bitcoin website. I would rather the bitcoin didn't go through my website to prevent any security issues.

What happens is one user pays another user, and when that happens my website delivers the digital goods instantly.

All I need to do is check if the one user pays the other user. But the problem I can't find a way to do that easily. 

I was going to use the blockchain api to check, but if they pay through a website like cryptsy, I can't check because it goes through multiple addresses.

The only solution I've found so far is to make them use the bitcoin wallet, or use an escrow service.

Escrow is my last option, because it always has a fee, and I really want this to be user to user.

I could really use some suggestions!

Thanks!(:
I think what you really need here is to be able to, on demand, get a new address for the receiver that is specific to a new order. So, for example, if the receiver of the coins is to get 1 BTC, then you get a new address for that user, associate it with the order, and as soon as it receives the coins you know that this order has been fulfilled.

It may not be so easy to get the user (receiver of funds) to give you a big list of their addresses ahead of time, though. This is where something like BIP32 wallets may come in handy. With Hierarchical Deterministic wallets, you can get an extended public key and generate addresses for someone else as needed without ever needing to know the private keys for those addresses. 

Not all wallets are HD wallets, and probably even fewer support getting an xpub to give out to someone for generating new addresses on the wallets behalf. You'd have to do some digging to find a wallet that would let you do this. Obviously, you wouldn't be able to force the payers to use this type of wallet, but if there are relatively few receivers (merchants) you might be able to get them on board with using a more fully-featured HD wallet to receive their payments.

More info: https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki