Determine who is using a Word file?

[Robert Crandal]

There are about 5 workers who have access to the
same Word document. If somone opens the file
first, they will have sole write access to the file...if
any of the 4 remaining users open the file, that file
will open in "read only" mode.

My question is, is it possible to determine the
username of that one person who has write access
to the file?? I just thought it would be nice if I could
display a message box that informs people who is
currently using the file or the one person who is
NOT in "read only" mode.

thank you