Word 2004 for Mac has faulty document merge

I'd like to have several people work on their own copies of one
document, and then merge them back into the first, and see the changes
of each person. I tried testing this out with Word 2004 for Mac, by
first creating a single document, then making several copies (using
Save As..), each with a different name in the filename (FILE - Bob,
FILE - Sam, etc.). I opened each one up, changed my user information
to that person's name, and made changes to the document, with Track
Changes on. I did the same for each file/user.
Then, I opened up the original document, changed my name to Bob
Reviewer, and tried merging it with each file, using Merge Documents.


Here's the screwy thing: Even though the dialogue box made it clear
that I was merging the selected file into the current document (i.e.
"FILE - Bob" into "FILE - original"), the result was that the original
file remained unchanged, and I was now looking at the copy with the
changes! In other words, it had opened "FILE - Bob" with the tracked
changes marked, but didn't do jack to "FILE - original"!