how to merge workbooks? formula issue

I want to merge 3 different workbooks because they all link to eachother and so mind as well have them in one larger file.

The problem is that when i copy and paste the contents (either or normally or just 'formulas in paste special) or if I try to move the whole worksheet it changes the formulas slightly.

In each workbook, each worksheet references other worksheets in each's formulas. Also, each workbook references the other 2 workbooks.

When I try to merge them, the old worksheet reference is inserted into the new formula in the merged workbook. For instance, it will insert [PortReportPerform.xlsx] into any given formula linking back to the old file. This causes a lot of references errors. How can I copy all of the formulas and cells (which is a lot), without excel changing anything in the formulas?


THANKS!~