Target Multiple Countries with one feed

How are people targeting multiple countries and multiple currencies?

Google recommends one feed to target different countries. I am based in the UK and want to target UK and US, but I am getting issues with my feed saying ‘Missing value [price]’ and ‘Invalid currency [price]’

How do we include currencies for both GBP and US Dollars in the feed or do we not need to do this?

If I create second feed for US then Google reports a ‘duplicate product’ issue