Sorry if this is threadomancy, but I do recall some early robotic walkers having six legs, always keep three planted to make a stable tripod, the move the other three forward, lower, and move the first three.
Again, I don't recall if it's worth the effort, but if you could lower the center one on one side, and the fore and aft ones on the other side...
Or, just say these are 'parked'.
Doug