Not a physical link, just an electro-mechanical gadget in the stick unit to provide feedback based on data provided electronically from the other stick. Kind of like those video-game joysticks.

You could also generate a small video display on a PFD/MFD showing stick force. But that would be less intuitive...you would have to think to look at it. But the stick feedback thingy would only work if you had your hand on the stick.

Or maybe change SOP to require the PF to call out his control inputs in situations where the airplane is not performing as expected.

Or just send everybody back to piper cubs for 100 hours.