Take some customizing

1) As you know, MT5 does not allow us to import historical data; whereas, MT4 allows us to import historical data from another source.  

2) Is it possible to have a work around solution?

For example at 22:01 the EURUSD is at 1.23080 (MT5 data) and the extern data is for another commodity is at (1550.50). Can we be innovative and divide the external data (csv file) by 1000? This will give us a price of 1.55050 and we can add this offset to the EURUSD. In this way, we can force MT5 to perform optimization on the EA based on the offset of the csv file.  

I am open to other ideas.