Is it possible to create named graphs by virtual graph mappings?

Hi Stardog Team,
I am mapping a Document-DB to Stardog as a virtual graph.
As I am using named graphs in stardog db to identify partial graphs,
I would like to generate named graphs dynamically by mapping a document id to a graph name in the virtual graph mapping (using SMS2).
I guess this is not possible, as the virtual graph itself is a kind of named graph and named graphs can't contain other named graphs?
The documentation is not that clear for me in this point.
It states that named graphs are not possible in the virtual graph mappings of R2RML.
But what about other mapping languages like SMS2?

Thanks in advance for looking into this issue,
Steffen