Excel Pivot Tables (with calculated fields)

I have a table with 6 columns (primary group, subsidiary, COO, month, and metric -which can only be Cost and Units Produced in the rows- and also values).

I created a Pivot table with the primary filter being "primary group", column headings layered into COO, subsidiary, and metric, and rows being the month. Then I added a calculated item under the metric, "Cost / Units Produced".

However, when I select a primary group (using the filter), all the unrelated subsidiaries are also appearing in the pivot table (albeit with no values). I am confused. Can anyone help?