The Draft Facebinder Tool takes multiple faces from single or multiple geometries and creates a new linked face from the selected faces.
For Detailed Information including Python Coding Details see:
https://wiki.freecadweb.org/Draft_Facebinder
To use the Draft Facebinder Tool select the faces you would like to include into the face binder object, then select the Facebinder Tool icon.
The Facebinder object can be edited late to include or exclude faces.