Do you mean the way of getting the data 3 monthes by 3 monthes.I can make it with this way.
for each number from 90 to ( the number of days you want the counter to stop on for example 182 (that means that we will get the data of the last 6 months 3 by 3) by 90
you will now form your request.In the start days parameter set it to number - 90 and the end day to the number.that’s it! now get data from the api with this url you have.