Hiding Specific Fields on Pivot Table Fields

Hello guys,

Does anybody know any way to hide specific fields on the Pivot Table Fields List?

Explaining a little bit better....

I have a huge database, with many columns as volume sold, price, cost and so on.
And still, many calculated field.

The problem is that there too many fields on the list where I select what I want and most part of them are used only on the formulas. So I will never use it on the "visual" part of the pivot table.

To avoid this mess, I would like to hide all unnecessary info.

So even with many columns, it should present to the final user only some of the calculated fields.

See the example (and sorry, but my Office is portuguese). I have to let only part of these fields.

How can I do that?

Thanks in advance.