Summarizing/grouping together columns

If I understand correctly, perhaps:

Column =
  CONCATENATEX(
    FILTER('Table',[Customer Name] = EARLIER([Customer Name]) && [Region] = EARLIER([Region]))
    [Customer ID],", "
  )

Hi Anonymous ,

Try this one:

Column =

VAR _customer = CALCULATETABLE(DISTINCT('Table'[Customer ID]), FILTER('Table', 'Table'[Region] = EARLIER('Table'[Region]) && 'Table'[Customer Name] = EARLIER('Table'[Customer Name])))

RETURN CONCATENATEX(_customer, 'Table'[Customer ID], ",")

 

Anonymous -

Measure solution attempt:

Measure Modified Customer ID = 
IF (
    ISFILTERED ( 'TableName'[Customer Name] ),
    CALCULATE (
        CONCATENATEX (
            DISTINCT ( TableName[Customer ID] ),
            TableName[Customer ID],
            ", "
        ),
        ALLEXCEPT ( 'TableName', 'TableName'[Customer Name], 'TableName'[Region] )
    ),
    BLANK ()
)