Rails - Nov 2005 - Blob tables

I''ve got three tables listing_photos, listing_movies, and file_blobs. 
Both listing_photos and listing_movies have a foreign key to
file_blobs where a blob of the file is contained.  Are there any
downsides from a rails point of view doing it this way.  Is a simple
case of doing something like this in the model:

class FileBlob < ActiveRecord::Base
   has_many :listingMovies
   has_many :listingPhotos
end

Will rails understand that the row can belong to either model?

--
Marlon