[OS X TeX] .bib files

[Itamar Francez]

Hi,
I am using MacTex, and until today I have always had just one big  
folder with all my .tex files in it. Now I would like to organize  
that folder into subfolders, but when I started a sub-folder with a  
paper I'm working on, I got this problem that bibtex doesn't find any  
of the references. This problem goes away when I put a copy of  
my .bib file into the subfolder where this particular .tex file is  
sitting. Is there a way around having to keep a copy of the .bib file  
in every subfolder?
thanks, Itamar.