Can you please better detail what do you want to achieve?
If I understood well you have created some account mappings in FDM (Activities > Maps)
And you want to compare source account in you mapping with a column in your file? Why would you want to do this?
I think that it would be better if you explain what you want to achieve so we can advice.
Thanks Amores , for the reply .
I will get back to you with valid example.