Actually there is a field View in JBRJ and other transactions. With this field it is possible to choose Portfolio Hierarchy Node.
But the field is hidden. (se38 -> IAFWCH_VIEWOUT) Hidden or not - It depends on the settings of Analysis structure.
SM30 -> JBVRMBBF -> Field "Segment Level Characteristic Category in Analysis Structures"
If you set "Flexible segment level characteristic (views), you can create several views for one Analysis structure. And you can append different characteristics to View-Analysis structure. And you can choose different PH nodes.
If you leave "Fixed segment level characteristics" you can create only one view and "View" field in reports will be hidden. Because you will use all characteristics and then you don't have to choose different node, i think.