so say i send btc from wallet(a) to wallet(b) and the change to wallet(c) and the fee is 0.0003 i then send btc from wallet(c) to wallet(d) this fee should cover the transaction from wallet(c) to wallet(d) and from wallet a to b&c and both should confirm quickly without any transactions being invalidated? if not could someone please outline how to do it like above if possible, thanks