Nope, there is no way to guarantee that the customer will click on the corresponding “Add to Cart” button for the same currency when you have two buttons for each product in different currency.
This is why it’s done through “Buy Now” type buttons which is a single checkout per product (it eliminates the possibility of customer mixing things up in the cart).
I have intention to add an option so a secondary equivalent price for each product can be displayed next to the primary price (eg. USD $50 or AUD $55) but the cart will still have to process the transaction in the primary currency.