>>360421305
With that bone setup: rotation constraints to the legs. I've got something similar for mine and it works great though it's a shitload of constraints to set up. Middle chain should be 50% constrained to each leg. Each chain should be half strength for the top most bone and full strength for the second one down. Only do the two chains in front of each leg and the middle one (10, 11, 12, 1, 2 o'clock bones).