Adding Columns to an existing grouped data set

[Anonymous]

Hi All, 

I have a table that has been grouped from a dataset. This is working correctly. 

I have added a column to this table and mergered it to the power query table. 

My problem is that as I update the grouped data my unique reference also updates, meaning my additional column data moves to the incorrect row. 

Is there another way round this?

TIA

[lbendlin]

Please provide sample data in usable format (not as a picture) and show the expected outcome.