System-wide policy to install documentation? Including non-dfsg docs?

["James Youngman" <jay@gnu.org>]

Is there any way that I can set up a policy or default like this?
(I'm running lenny)

1. Installing foo where foo Recommends: foo-doc causes the
installation of foo-doc.
2. Installing bar-doc where bar-doc Recommends: bar-doc-non-dfsg
causes the installation of bar-doc-non-dfsg

(In other words, always install the documentation, even if it is non-dfsg-free)

I'm happy if this only works via (e.g.) apt-get, if that restriction is needed.

Thanks,
James.