Tvheadend

I've only recently started using TVHeadEnd and already have a fairly large library of tv shows, I'm trying to find a way to stop TVHeadend not recording episodes I may already have.

As an example lets say I have all episodes of NCIS from seasons 1-6, but only about 75% of the episodes from 7-13. I want to setup TVHeadend so it only records episodes from season 7 onwards.

At the moment I TVHeadend is recording all the NCIS episodes that are broadcast so there are 100+ episodes being recorded from seasons 1-10 when I might only need about 20 of them. As season 7 was originally broadcast from Sept 2009 I could use that as the filter.

I'm pulling data from Schedules Direct if that helps.

Thanks for any help you can provide.