Best Exchange rate

Heya guys - currently in the USA and flipping cards left right and centre. Maybe a way that based on the current exchange rate/fees for each card, it automatically takes it from the best rate, then reverts to whatever card is set?

i.e may card is set to say my Lloyds Debit card. I use it in the USA, and it takes the money from my WeSwap card, then automatically time travels to my Lloyds?

It’s something I’ve been doing manually but would be great to be automatic!