Import 2 or more csv file data to the table If path of the file selected by user

Hi,

   I Import a .csv file data into table to use codeunit. I am not using XMLPORT for this. If the same pk  field data comes again then old related fields updated by new data. this is done perfectly. but now i have to import more than one csv files.

so how can i do this because in my code i have open only one file