repeater with several levels

[f-pasquier]

I have a repeater (could also be a page set) which I would like to list items which are on two levels (OLAP data source).
Example:
- A
    |_ Abc
    |_ Def
- B
- C

Suppose the dimension has two levels, like in this example and I would like the repeater to "repeat" for all the descendants, meaning for 5 items. I did it with the Descendants function but it does not work. When I test the query of the repeater I can see what I expect, but when I run the report, I get errors and even in some cases the TM1 server to crash.
Is there a "right" way to solve this problem?

thx folks