Matrix - Total to All when filtered

Hi, guys,
I am quite struggling with this one:
I need this table:

I need to get the Total of "Total by BU" to Total by selected BU. 
I am able to retrieve the Total By BU using this measure:

var __SelectedBUs = VALUES('sample'[BU])

var __calc = CALCULATE(SUM('sample'[Something]),ALL('sample'[Item],'sample'[BU]), 'sample'[BU] IN __SelectedBUs)

However, I can't figure out how to put the total to All rows in the next column.
There's an active "Item" slicer:

What it should do is that it takes all "BUs" that is filtered by "Item", then toss the "Item" filter out, SUM(Something) of all the filtered BUs together and return it back to all rows. Similar to "Total By BU" but return the total to all rows.