Autopopulate due dates in new groups

Ive been looking a way to autopopulate the due dates from a group (items and subitems), that will be clear each month. This means the group will stay the same (or i can make it duplicate), and set the same dates only varying the month.

Ex: In the file its the group i want to duplicate or clear, and then in the new one automatically set the same dates but for september.
If there is another way to make it easier Im all hears! I just not want to set the date manually for each every month.