Metric based on row value of a table

[danielgarciamej]

Hello

I have the following table

CAR    -     MODEL     -   COUNTRY

Audi - A4 - Spain
Seat - Ibiza - England
...

I want a new column with the total cars selled, based in the country of each row.

I tried this expression and works: Pick(1,MODEL)
The expression returns the model for each row of the table.

But if I try this expression, doesn't work:
COUNT(TOTAL DISTINCT {<MODEL={'$(=Pick(1,MODEL))'}>} [Id Ad])

How can I calculate a metric based on the value it has in each line of the table?

Thank you so much.