Getting a fight stick to work with Intellivision

First of all I understand it’s not a catch-all solution. Some games are designed to be used with a 16 way joystick, and those games should not be played with an 8-way fight stick. So mainly I want this for 4-way games like Burgertime and Lock N Chase and maybe a few games where quick switching in directions benefit me more than 16 distinct directions.

Second, the easiest way I know you can make a discrete input fight stick work with a console you have no idea how to replicate the joystick code is by pad hacking. For most consoles that would be perfect. However there is one wrinkle that prevents and easy one-to-one wiring.

Not only does it have a 16 way pad, but, if you take apart the pad, you’ll see 16 buttons in the round around the pad. So there are 16 separate actuators, with only one being pressed at a time.

This is unlike every other console with an 8-way stick, where there are only 4 actuators for north, south, east, and west, and the diagonals are 2 noncontradictory cardinals actuate together.

Is there already some sone sort of circuit which can convert 4 discrete wire signals, with diagonals equalling 2 cardinals, and turn it into 8 separate wires that can be wired directly into the Intellivision diagonals and cardinals.

May I have either a model name or a website where I can find this circuit if it’s premade and easy to order, if one exists?

If one doesn’t exist, my joystick maker, who apparently doesn’t know how to do digital actuation of analog sticks, (but might be able to if given directions, but we don’t need it thanks to using a Cthulhu) but is competent enough to build and understand what I want done in terms of multiconsole and ambidextorus and reassignable.