Perhaps using data sets is a solution. Create an OQL query specifying the above and show the result in a report.
https://docs.mendix.com/refguide6/data-sets
However, a report is readonly so if you want to use the data you're retrieving, you might have to take a different approach.
We would like to do the followings:
1) mapping from one entity member to 2 or more members,
2) joining multiple entities into one entity like SQL's 'JOIN', and
3) grouping entities and summing up data like SQL's 'GROUP BY' and 'SUM'