Freaky for that combination, just wire the 3-way switch exactly like you would a standard tele (with a jumper that connects the two side of the switch across 4 lugs) then solder the middle pickup hot lead to any one of the lugs that has the jumper on it.

In your scenario, the middle pickup is continuously "on", so adding it to the jumper wire puts it in the circuit with either or both of the other two pickups.