Help with Aggregations and Composite models.

Hello guys,

I'm starting to play with aggregations and composite models on PowerBI with Redshift as a datasource.

To make things simple I have one import table with aggregated data and another table with detail and DirectQuery.

Then I have a dimension with a lot of cardinality, something like this:

ID, SITE, ID_SITE_GROUP, SITE_GROUP
1, www.1.com, 1, MAIN

2, www.2.com, 1, MAIN

3, www.3.com, 1, MAIN

4, www.4.com, 2, SECONDARY

5, www.5.com, 2, SECONDARY

and so on...

I tryied two different approaches without the expected result.
First, I connected this dimesion to both aggregated and detail table, like this:
Sample Model

What I was expectig is that when I used dim_site.site_group in any visual, PBI used imported data and if I used dim_site.site then make a DirectQuery over Redshift. It didn't work because PBI always throws a DirectQuery when using this dimension.

Does this make sense? I mean, is this the correct approach for what I'm trying to achieve?

The second approach I tryied was to have this site_dimension separated, more like an snowflake model. It didn't work either.

Anything will help, thank you!!