Mapping Same Column to Multiple Outputs, also to undefined Output

[ebhills]

I know we intentionally check to make sure column isn't / can't be mapped to 2 outputs, but actually think that could be useful. Beats having to create a copy before or after the Map.
Also, want ability to pass through an 'extra' column without it being defined in the map. Might call it something like 'Extra 1', 'Extra 2' etc.