I am kinda new to excel but I had recently spent some time on a similar
sheet. I believe what you do first is go to data, get external data,
import text file, delimited, separate by comma. This will import it
once. Then go to data, get external data, refresh data on file open.
You may want to uncheck prompt for filename on refresh. I do not have
my sheet here with me now, but it seems to me I had to also check
overwrite existing cells... 2nd from the bottom. You may or may not
want to do this last step depending on how your sheet is set up, but
you can experiment. I think this will do what you require, but I'm not
sure. Hope it helps.

Peter