There actually is a way but you won't find it on the Hyatt website and it is not foolproof. What I do is the following:

1). Choose the initial date for each hotel you are considering and then serach using Travelocity and its flexible search option -- that will tell you the least expensive nights in a 30 - 60 day date range.

2). Choose that date and input it in Kayak for that region and select Hyatt hotels -- that will confirm that the Hyatt and Travelocity and what other booking engines are within sight of one another.

3). Then go to Hyatt.com and input that specific date(s) and whatever discount rate you may be entitled to -- Senior, AAA or the like -- that will then likely pull up the lowest rate for a given time period at a given hotel(s) within a certain region.

4). Otherwise, you can serially input each date into Hyatt.com with whatever discounts you may be entitled to but this likely will take much much longer.

The above is not always foolproof as there can be minor flucuations among different booking engines that might not be picked up -- but this is the easiest way to accomplish what you wish withing a short time frame.