cumulative by group

Hi,

I'm trying to do a cumulative sum by group. I've tried different solutions but none seems to work.

I have a table with millions of entries of booking made and they all are grouped by channel group

I was able to create a cumulative sum for the number of nights as in above picture.

The main problem I get is that it does not sum indevidualy per group when all groups are selected. It groups the nights and shows the same value for all.

this is how I'm calculating the cumulative sum

cumulative nights = 
CALCULATE([nr_nights total for group],
FILTER(ALLSELECTED('gc_reports bookings'),
'gc_reports bookings'[book_date].[Date]<= MAX ('gc_reports bookings'[book_date].[Date])))

The nr nights total for group is a quick mesure like this

nr_nights total for group = 
CALCULATE(
	SUM('gc_reports bookings'[nr_nights]),
	ALLSELECTED('gc_reports channel_groups'[group])
)

Once you select a specific group, all works.

Sorry if this is a dumb question but what am I doing wrong here?