Ranking within a group

Hi,

Please check the below picture and the attached pbix file.

I tried to create a sample pbix file like below, and I hope the below can provide some ideas on how to create a solution for your dataset.

Sales total: = 
SUM( Sales[Sales] )


Rank by sales: =
VAR _SKUranking =
    RANKX ( ALL ( 'SKU Master'[Parent SKU] ), [Sales total:],, DESC )
VAR _CustomerslistbySKU =
    FILTER (
        SUMMARIZE ( ALL ( Sales ), Customer[Customer], 'SKU Master'[Parent SKU] ),
        'SKU Master'[Parent SKU] = MAX ( 'SKU Master'[Parent SKU] )
    )
VAR _Customersranking =
    RANKX ( _CustomerslistbySKU, [Sales total:],, DESC )
RETURN
    SWITCH (
        TRUE (),
        ISINSCOPE ( Customer[Customer] ), _Customersranking,
        ISINSCOPE ( 'SKU Master'[Parent SKU] ), _SKUranking
    )