Without VPN, clients connect to the pineapple, through a computer via ICS, to the internet
{Internet} <--- {Computer} <--- {Pineapple} <--- {Clients}
What I want is
-------------{VPN}
V ^
{Internet} <--- {Computer} {Pineapple} <--- {Clients}
So all pineapple client's traffic will route to the internet through a VPN.