Help please : Downloader Merge problem

When iam merging new data from source to destination , i would have to select each security alone from source to each each security in destination : one by one .
This takes too much time to be done one by one on 200 securities or more .
IS there a way to select all securities in source file to be merged with all securiteis in destination file all at once . ???


Any help in this is appreciated .

Thanks

Don't think there is randommuse