If the platform can not put the 2 on top of each other in the same chart, it should at least have the underlying EUR/USD cash in the quotes displayed Thanks
In Schwab thinkorSwim you can chart /6E - EUR/USD, though I'm not entirely sure this is legit. You should check with Schwab to figure out where they're getting the data.
MultiCharts, which I used most in the past as backtesting and charting software. They have lots of options to display different data feeds at the same time in same chart and more.