[Dx4win] DX4WIN filter question

[George]

I need to filter all my QSO's from 1/1/2013 to 1/31/2013, tomorrow, and only
filter for the unique countries and write to a file that others without
DX4WIN can read. 
We have a contest in our DX club, WNYDXA, for the most countries in the
month of January.
I was able to filter all contacts in January but also need unique countries,
no dup countries.
How can this be accomplished in DX4WIN version 8.05?
Thanks.

George  W2YJ