Lets say for whatever reason (deliberate or accidental) Bitcoin hardforks into two chains.. I have 10 bitcoins in my wallet, on chain 1 I would like to send those 10 bitcoins to address 12345 and on chain 2 I would like to send those same 10 bitcoins to address 19876..

Assuming both chains have nodes still relaying txs amongst both chains, how do I prevent the first tx from being applied to the 2nd chain accidentally? 

Is there a way to specify to only include this tx if block x hash = ?

Any other way to keep the tx on one chain and not the other?