It sounds like what you need is the opposite of the Extended Family Chart - that is: an Orphan Record Dataset (in report or chart format - or just added to the regular FTM filter).
With the "Include everyone in this file" UNCHECKED
Extended Family Chart - includes everyone related to the selected person by blood OR marriage.
Orphan Record Chart - would include everyone in this file NOT related to the selected person by either blood or marriage.
This is another one of my annual enhancement requests. You can add to the chorus, here:
http://ancestry.qualtrics.com/SE/?SID=SV_er4cyPjj5BJKIZf
With the "Include everyone in this file" UNCHECKED
Extended Family Chart - includes everyone related to the selected person by blood OR marriage.
Orphan Record Chart - would include everyone in this file NOT related to the selected person by either blood or marriage.
This is another one of my annual enhancement requests. You can add to the chorus, here:
http://ancestry.qualtrics.com/SE/?SID=SV_er4cyPjj5BJKIZf