This is not true for all the Verandah dividers on the Wonder. We had the Walt suite and the 3 adjacent 4A staterooms for my wife's 60th birthday. We were able to have them open the divider between the Walt and room 8028. The divider between 8028 and 8026 was fixed and could not be opened. We didn't try the one between 8026 and 8024. It did take some work and the had to call in a carpenter to open the one divider, since apparently it hadn't been opened in a long time.
Not sure how you can tell if the divider can be opened between any particular pair of rooms. I would guess that there is a better chance if the rooms are actually have a connecting doorway.