How to not display redundant information in table Views?
You can try Views Field View module.


Create a "secondary" view of Field2 contextualy filtered by
relationship with EntityA.
In your main view, use Field1 and new Views Field of your "secondary" view (this field type is added by module).
Set up that new Views Field in your view to pass proper argument to "secondary" view contextual filter (and therefore show relevant Field2s related to EntityA)