I'm not sure I understood the question but it's definitely possible to define operations to cascade for a one-to-many association (see the section 6.2. Collection mappings). Below, an extract from the Chapter 21. Example: Parent/Child:
  
  
  You can address the frustrations of
  the explicit call to save() by using
  cascades.
<set name="children" inverse="true" cascade="all">
    <key column="parent_id"/>
    <one-to-many class="Child"/>
</set>
  
  This simplifies the code above to:
Parent p = (Parent) session.load(Parent.class, pid);
Child c = new Child();
p.addChild(c);
session.flush();
  
  Similarly, we do not need to iterate
  over the children when saving or
  deleting a Parent. The following
  removes p and all its children from
  the database.
Parent p = (Parent) session.load(Parent.class, pid);
session.delete(p);
session.flush();
  
  However, the following code:
Parent p = (Parent) session.load(Parent.class, pid);
Child c = (Child) p.getChildren().iterator().next();
p.getChildren().remove(c);
c.setParent(null);
session.flush();
  
  will not remove c from the database.
  In this case, it will only remove the
  link to p and cause a NOT NULL
  constraint violation. You need to
  explicitly delete() the Child.
Parent p = (Parent) session.load(Parent.class, pid);
Child c = (Child) p.getChildren().iterator().next();
p.getChildren().remove(c);
session.delete(c);
session.flush();
  
  In our case, a Child cannot exist
  without its parent. So if we remove a
  Child from the collection, we do want
  it to be deleted. To do this, we must
  use cascade="all-delete-orphan".
<set name="children" inverse="true" cascade="all-delete-orphan">
    <key column="parent_id"/>
    <one-to-many class="Child"/>
</set>
  
  Even though the collection mapping
  specifies inverse="true", cascades are
  still processed by iterating the
  collection elements. If you need an
  object be saved, deleted or updated by
  cascade, you must add it to the
  collection. It is not enough to simply
  call setParent().
References