Sort grouped bar chart based on previous month data

[lone_wolf]

Dear experts,

I have a grouped bar chart here, where the sort condition(by expression in descending) is like: 

where,

MonthYear are the bars

previous_MonthYear considers previous{month(Today()-1)}

MonthYear_max_BN contains the max month of each group.

This sorts the graph as below, sorted based on descending order of latest month if previous month data(eg: oct ) doesn't exist, else sorting is done based on previous month's data.

Now I want to display the data in descending order such that the bars are sorted like: (groups sorted by previous month eg: Oct)-->(groups sorted by current month eg: Nov)-->(groups sorted by previous-to-previous-to-previous month eg: Sep)-->(groups sorted by previous-to-previous-to-previous-to-previous month eg: Aug)-->So on..

I tried to do the grouping like this using aggr(), but it doesn't seem to work, except for the max(MonthYear):

I am unable to write a condition instead of max(MonthYear) in aggr() for eg: max(date(MonthYear-1,'MMM YYYY')), it doesn't seem to work.

I would really appreciate if the above two scenarios can be combined somehow.

Thank you in advance. 😊