Filtering the changelog

Hi,
    I was wondering if there is a way to restrict generateChangeLog or updateSQL to refer to just a subset of the tables in a database. I am thinking particularly of when creating a baseline from an existing database. This is a case where contexts cannot be used.
For exampe, if I have a database with 500 tables how could I tell liquibase to generate a change log for just one of them or how could I tell it to not generate change logs for 200 that are not of interest?
As far as I can tell the only way to do this at present is to hand edit the changelog for the entire database. Is there a better way?

Regards,

Bruce.