Resistive switch?

Hey all,

I want to butcher a Gamepad's buttons so that I can connect a resistive
touch pad to it instead (Ie. two sets of interleaved metal fingers that
you bridge with your hand). I wonder what the best way of doing this
would be? Could I put a transistor over the original contacts, and
switch it with the current that flows between the sets of fingers when
bridged? Or am I totally on the wrong track?

Cheers,
Nicholas Sherlock