How to get sub lists of a list

Hi all,
I'm using Arrays.sort(Object[], Comparator) to help sort some of my objects. However, I now have a need to create sublists off of a sorted list
For example I have a list of following objects
Person[] person = new Person[3];
// The Person constructor takes
// LastName, FirstName
person[0] = new Person(Goodyear, Nancy);
person[1] = new Person(Clark,Stanley);
person[2] = new Person(Goodyear, Elvis);
I sort them
Array.sort(person, Person.LastNameComparator);
The list ends up being
Clark, Stanley
Goodyear, Nancy
Goodyear, Elvis
However, what I want the sort interface to return is a an array of sub lists (each sub list has only duplicates in them) as follows
SubList1: Clark, Stanley
SubList1: Goodyear, Nancy
Goodyear, Elvis
Are there any Java APIs or some other techniques available to do this?
Thanks in advance
PJ

I have always used something akin to the following:

class Person implements Comparable{
    private String firstName;
    private String lastName;
    public String getFirstName(){
        return firstName;
    }
    public String getLastName(){
        return lastName;
    }
    public Person(String aLastName, String aFirstName){
        firstName = aFirstName;
        lastName = aLastName;
    }
    public String toString(){
        return lastName + ", " + firstName;
    }
    public int compareTo(Object o){
        Person aPerson = (Person) o;
        return this.toString().compareTo(aPerson.toString());
    }
}

public class Test{
    public static void main(String[] argv){
        new Test().run();
    }
    public void run(){
        java.util.Map aMap = new java.util.TreeMap();
        Person aPerson = new Person("Goodyear", "Nancy");
        this.addPersonToMap(aPerson, aMap);
        aPerson = new Person("Clark", "Stanley");
        this.addPersonToMap(aPerson, aMap);
        aPerson = new Person("Goodyear", "Elvis");
        this.addPersonToMap(aPerson, aMap);
        java.util.Iterator anIterator = aMap.keySet().iterator();
        while (anIterator.hasNext()){
            java.util.Collection aCollection = (java.util.Collection) aMap.get(anIterator.next());
            java.util.Iterator iter2 = aCollection.iterator();
            System.out.println("List:");
            while (iter2.hasNext()){
                System.out.println("\t" + iter2.next());
            }
        }
    }
    public void addPersonToMap(Person aPerson, java.util.Map aMap){
        java.util.Set aSet = (java.util.Set) aMap.get(aPerson.getLastName());
        if (aSet == null){
            aSet = new java.util.TreeSet();
            aMap.put(aPerson.getLastName(), aSet);
        }
        aSet.add(aPerson);
    }
}

Thanks Joel