I'm not sure I understand the limitation you are hitting. Are you seeing problems during model design or in Report Builder after you publish the model?
I'm not aware of any existing issues like this. Here's a few things you could double check:
- The entities in the model that correspond to the "other" tables all have IsLookup=false and Hidden=false
- The roles in the model from the main entity to the "other" entities all have Cardinality=OptionalMany
- I assume you are using Model Designer to build the model against a SQL database, not generating the model from an Analysis Services cube.