Comparison of data between three spreadsheets
 

I want to compare data between three spreadsheets in three different XLS
files.
More specifically, I have a project progress report that I run every three
weeks. I want to do a comparison of the finish dates that are attached to
the projects. If the date cell was flagged with a red color in the last
report and the report before that, I would like a flag (of some type) to let
me know that that project should be looked at this week.

My question is can I do this? If so, how? Or would it be more effective to
develop a little database in MS Access that can do this for me?