I have been able to use the output of a view (base view, interface, derived view) as an input for another view by specifying the view in a where condition of another view.
For instance, you could use the below query, to get the result of view2 based on the results of view1.
Select * From view2 Where field12 in (Select field11 From view1)
In Virtual DataPort Administration tool, you could create this query graphically by specifying the Where condition using ‘in’ operator in the Selection view of view2.
Where field12 in (Select field11 From view1)
Hope this helps.