I have a set of data with transactions with various currencies, I need to look up the daily exchange rate from a list that is set up as below selecting the column based on the currency for each transaction.

At the moment my workflow is set up to filter by each currency, look up the value for each flow with a Join tool then combine the data again (screenshot below), which looks pretty redundant and would become particularly messy once more currencies were added.

Any ideas on what would be the best way to simplify this?
Thanks