[OS X TeX] References across files

[Alain Schremmer]

Suppose you are writing a novel about a family but you have not yet  
decided what the names of the various characters are.

The obvious idea is to create a separate file with a genealogical  
tree, in which you would have, say, "Tom" so that, as you write the  
various included chapters of the novel, instead of typing "Tom", you  
would type the reference of "Tom" in the genealogical tree. Then, as  
you would typeset, all the occurrences of the reference would be  
replaced by "Tom".

Now the equally obvious question: Is there actually a way to do this?  
(in LaTeX)

Rather hopeless regards
--schremmer