UPDATE: It looks like Microsoft Dynamics GP Support Services Blog had posted this article before Collins Dynamics GP blog. You can read both anyways.
May 31, 2012: Nicole Albertson from Microsoft Dynamics GP Support Blog explains Table Links in Extender – Nicole, which can be used to remove an Extender record when the master record is deleted.
June 6, 2012: Collins Dynamics GP Blog shares the same topic on it’s post Table Links in Extender – Collins.
The concept of removing Extender records when master record is deleted is very very crucial. This post, hence, is important.