Merge Shared Workbooks into a Master Workbook
 

I have a Master Workbook and 4 other copied Workbooks for North, South, East,
West. The copies have certain areas that can be edited. Changes are inputed
by different users on the copies. When I try to merge the changes from one
of the areas, Excel goes blank and freezes up. The size of the Workbooks is
around 45mb. Is there another way to merge these files? How else can I
merge the changes into the master?