I believe you are referring to: Erik Zapetal’s “Balanced Suspension" concept. This system de-couples the 4 vehicle suspension modes passively. His SAE Technical Paper 2000-01-3572, available from:
Alex Moulton demonstrated a couple of Minis, one with for-aft coupling and one with lateral coupling of the hydromounts. Also Gates (air springs) have occasionally suggested a passive cross linked system.
Here are some people working on a commercial version: