MDX NewBe: MAX Of SUM GROUP BY

Hi.

I will try to abstract my problem to an example, simple as possible.

In a relational database exists 2 tables: Cars (containing car name and car id) and Costs (containing costs caused by cars - with columns like cost_id, car_id (fk to table cars), cost_category (something like 'buy', 'cleaning', 'maintenance'), cost_date and costs)


In the olap cube I've 2 dimensions: Cars and Costs and a measure sum(cost).
How can I create a measure containing the max value of the sum(costs) group by car_id?
In the SQL world it would be something like



Code SnippetSELECT
MAX(COSTS_PER_CAR)
FROM
(
SELECT
CAR_ID,
SUM(COSTS) AS COSTS_PER_CAR
FROM
tblCOSTS
GROUP BY CAR_ID
) AS TBL






But how can I realize it in MDX for using it as measure?

Thanks in advance.
Greetings.
Anatoli Rejditsch.