Connect Datamart to Datamart - Chained Datamarts

Hi,

In my use case I have to provide an individual sets of reports (Power BI and Excel from Power BI) to several operational centers.

My idea is to create a Datamart for every center with a number of individual queries for facts to a central Oracle DB.

As most of these individual fact queries connect to same dimensions, I have put all the dimension tables into a "dimension" datamart.

Thought this to avoid dimension data is getting pulled with every individual fact query. 

But I fail to connect the Ops centers datamart with individual fact queries to the "dimension" datamart.

Tried with connection string, blank query, OData, Azure Analysis Service etc etc

Maybe my approach is completly weird and there is much better way to do.

Any help on the connection, or any better ideas are highly appreciated.

Many thanks in advance!

Regards

Gerhard