Calcualting Top 5 Customers

Hello All,

I have a questoin where I need to find the top 5 customers but with the categories as Tier1 and Tier2.

I have a table as below screenshot

Power Query:- 

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("hZQ7csMwDETvopozJkBSIOtcIZ3HZQq3vn8RfeBoyZWVyh6/pfSMhXS/T18yhUlu6aZRdf0acm7L5/L7I/xhiQe3WZgb8DwT13zwapl4EjhfC3Ad9ZqlFSti1GvxhINeLZX4oachNj5/6K1cgKdeT4Ok7fIJ8aG38KrMDXgR4qin0oijXi4ZeB71yn48I0a9OSlzo3I6juV6Ox3Hcr0d52Us18spiFHPy+m5UTkdx+l5Ox3H6Xk7zmcqdyvn+/nzUkyg4d4PR2ysiCLoWc6vgqp7UxCx864pwXVzhBqnCJfOKle2dbSlqVSypT9UabYf7nM52/q/bRtt90WjRPekb7vGERvXjSLdxo4r18iWVk7iqPspgr5UwDtjF7PzDBrT8N469I73zOMX", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Customer = _t, #"Begin of Week" = _t, Sales = _t, #"Customer Group" = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Customer", type text}, {"Sales", Int64.Type}, {"Customer Group", type text}}),
    #"Changed Type with Locale" = Table.TransformColumnTypes(#"Changed Type", {{"Begin of Week", type date}}, "en-ZA"),
    #"Added Conditional Column" = Table.AddColumn(#"Changed Type with Locale", "Tier1/2", each if [Customer Group] <> "Tier2" then "Tier 1" else "Tier 2")
in
    #"Added Conditional Column"

Where I have Tier1 and Tier2 customers that I have categorized as per user.

Now I am using a Area chart to show the top 5 customers as below.

I have filtered the top 5 customers by inbuilt power bi option under the filter's panel which filters the top 5 customers irresptive of the Tier1 or Tier2 which is expected.

Now the real ask here is,

   By Default the area chart should show the top 5 customers which are from Tier1 only.

   That means, Until user filters the Tier2 customers from slicer the area chart should show the top 5 customers from tier1             customers only.

   If user selects Tier2 only then it should show the top 5 customers from tier2.

But there are situations where user can select SOME OF THE CUSTOMERS from Tier1 and Whole Tier2 and vice versa.

For example:- 

If user selected, C3, C4 from Tier1 and selected Tier2 which by default selected all the tier2 customers,

Then in that case, top 5 customers in area chart should be, C3, C4 and then top3 from Tier2 customers.

Note:- As it is a sample data, I have jus included five customers under Tier1, but there are more than 20 Customers under tier1 and more than 50 Customers under Tier2.

Here I am giving the onedrive link for the pbix file.

https://1drv.ms/u/s!AmauTLNmHKexhGcs7UQE-SoJtnTZ

Request you to please suggest.

Thanks,

Mohan V.