Change in company structure left me out of the new salary range.

I work for a big company. Last year, they re-estructured and created new divisions. The new division where I was placed at has a better level than the previous one. My position was transferred to a similar one but this one has a higher salary range. I should be moved to the new equivalent position, anyway they haven't done that yet. It's not only me; about 3 more people are in the same situation. My salary is down for a bout 10,000 to the lowest of the new salary band. They made those changes about 8 0r 10 months ago. Are they obligated by law to adjust my title and salary to the new equivalent position? if other co-workers were moved at the time of the changes, should I get any retroactive compensation for being out of the salary range for this time?

I apprecaite your answers.