Text Import WIzard query

Hi Experts,

we are importing  some data to Sm using Text files. Unique key is reference.id in text file but not in SM Table.

SO what we need is, we have to skip few entries from import,  based on the data available in SM Table.

It is like, from SM database, we need to fetch the records based on  reference.id, Assignment group isin {'x','y','z'}.

then if, that reference.id present in Text file means, then we have to ignote that entrie to get imported.

In other way i can tell it as, i need to import the records from text file to SM Table,  which should not override the records, where Assignment group isin {'x','y','z'}..

how to achieve this in text import wizard??

 

Thanks in advance,

Regards,

Shalini R