You can use as many bounding boxes as you want. To do this, use the following API method to draw the area you want :

var instance = new AsukaDesigner('#myId'); // Create an instance of the main plugin class

instance.designer.drawBoundingBox('Circle' /* Rect by default */)

This method takes as a first parameter the type of zone you want (Rect if not defined), and as a second parameter the view on which you want the zone (current view if not defined).