How to make a package version different from the source version?

[Jérôme Marant <marant.logatique@fr.thalesgroup.com>]

Hi,

  I would like to split a single source tarball that contains multiple
  components which have their own version. These versions are different
  from the main tarball version.

  It looks like the python-gnome package does this, but I cannot see
  exactly how it works.

  How can I perform this?

  Thanks in advance.

-- 
Jérôme Marant