[graph-tool] How to see the relations between two groups of blocks in a bipartite network?

Hi, Sorry if I ask basic questions but I'm new in this. I have a bipartite network, with two types of nodes with no connections between the nodes of the same type, only between different types. I have run minimize_blockmodel_dl y minimize_nested_blockmodel_dl with different options but I always get separated blocks for each type of node: some blocks only with nodes of one type and the rest only with nodes of the other type. But I am really interested in the relation between this two groups of blocks. Any idea about how could I get that? Thank you very much. Best regards, Andrea