The Tribal Analysis Center published in October 2009 a document entitled "Pashtun Tribal Dynamics". If you work in an area of Afghanistan in a Pashtun dominated area this reference could be very informative and help you understand the many characteristics of the Afghan tribes and specifically the Pashtun tribes, clans, and villages. The document is an Adobe Acrobat PDF and can be accessed at the link below.
www.tribalanalysiscenter.com/PDF-TAC/Pashtun%20Tribal%20Dynamics.pdf