Employee appraisal: Survey use

Hi there,

For my  employees i want to make appraisals via the survey app.  The questions should go like this:

Competence 1 :  Motivation

Question 1: Demonstrates belief in the abilities of others

Question 2:Gives Praise ans open recognition

Competence 2: Resilience

Question 1: Maintains motivation and focus when under pressure
Question 2: Perseveres over a period of time to achieve an end result

and so on.

I would like to have a pivot where i can compare the answers'score (between the employee, the managers, the collaborators etc...), subtotalled by Competence. (The grand total is already shown in the standard list view.)

I've activated the pivot view on the answer's list view, but i can't seem to group the compentence (studio field added to each question)

I'm using Odoo 13.0+e online, with studio activated.

Any help is welcome, as i am trying to find a solution... :-)