I think you have the wrong idea about what a "coin" is (I also had this misconception for a while). A "coin" has nothing to do with the hash found to mine the b

I think you have the wrong idea about what a "coin" is (I also had this misconception for a while). A "coin" has nothing to do with the hash found to mine the block. All that happens is that when a block is mined, it includes a transaction that gives the miner 25 coins (Or whatever the current bitcoin reward is). So the coins are just a number, there's nothing that separates one "coin" from another "coin". It's like handing out dollar bills without a serial number on them. So if you move 20 coins from wallets A and B to wallet C, and then Wallet C moves those coins to wallets D and E, there's no concept of "whos" coins from A and B you moved into each wallet, it's just a count.