I have a basket of 10 tradeables, 3 of which are not in USD. I would like my backtest to run such that all executions are calculated in the FX but once the backtest is complete and it is time to combine all assets into 1 portfolio those not in USD will be converted over. How can I do this in RE? Is it a programming issue or a setting? Do I need to enter a FX rate in this process?