1. A computer-implemented method of generating an optimized pricing plan, comprising: accessing, by a computer, a hierarchy comprising a sequence of levels, each level comprising an objective function and a set of objective function constraints, wherein each objective function represents a primary objective or one or more secondary objectives; assigning, by the computer, a first fixed to a first item and a second fixed price to a second item according to one of the set of objective function constraints; preventing, by the computer, a rule violation resulting from the first and second fixed prices by de-linking the first and second items within a plurality of items; determining, by the computer, a mathematical programming model representing a pricing plan problem for an item group comprising the plurality of items, the mathematical programming model comprising a set of initial constraints; repeating, by the computer, for each level of the sequence of levels, until a last level is reached: adding the set of objective function constraints to the set of initial constraints; optimizing the mathematical programming model to yield an optimized boundary for the objective function; generating an optimized constraint from the optimized boundary; and adding the optimized constraint to the set of objective function constraints of the next level of the sequence of levels; optimizing, by the computer, an objective function of the last level of the sequence of levels subject to the set of objective function constraints to yield an optimized result, the set of objective function constraints comprising the optimized constraint generated from the optimized boundary of a previous level; generating, by the computer, an optimized pricing plan in accordance with the optimized result, the optimized pricing plan associating an optimized price with each item of the item group; determining by the computer, a number of price changes for ones of the plurality of items in accordance with the optimized pricing plan; determining, by the computer, when the number of price changes for the ones of the plurality of items exceeds a predetermined number of price changes; assigning a priority to the prices of the ones of the plurality of items that (1) have larger price changes, (2) are image items used to track competitors, or (3) have more stable prices; and changing the prices of the ones of plurality of items that have the highest priority.