As you said, foreign hands can be anyone who is alien in the region. That means NATO members, India, etc.
But you must then see which foreign hand really moves and directs Taliban. The answer goes straight to Wahabi charities based on the Gulf and in Saudi Arabia.
These “charities” are not only spreading terror in FATA and afghanistan, they are also supporting Wahabi cause of death in many other countries. In fact now the Wahabis have come home to Saudi Arabi.
Just read the news. Saudi Arabia is putting 1000’s of terrorists and terror sympathizers on trial.
BBC NEWS | Middle East | Hundreds face Saudi terror trials
Off course many in Pakistan or on this board would disagree due to their pro-Wahabi views. But facts are facts.