Customizing RBL and SURBL lists

[D . J .]

Greetings all:

I intend to eventually have local copies for the lists I wish to use, so it's important for me to figure this out.  Currently, I'm just trying to get SA to only do checks against the lists that I want to eventually check.  However, it still appearst to be checking all of them.  I've basically taken the 20_dnsbl_tests.cf and 25_uribl.cf files, copied them to my /etc/mail/spamassassin directory, and commented out the lists that I don't want checked.  However, as I said, it still appears to be checking things.  I have a feeling this is because the original 20_dnsbl_tests.cf and 25_uribl.cf files are still in the /usr/share/spamassassin directory, and simply commenting them from a later file won't change matters.  However, the catch is that from what I've read, I *don't* want to edit the files under /usr/share/spamassassin as they'll be overwritten upon upgrades, thus losing my customizations.  What is the best course of action to accomplish this goal?

Thanks!

- D.J.