Hibernate Query Question - Get most recent unique rows

Given the two classes at the bottom of this email, I'm having trouble
coming up with a Hibernate query statement that returns a list
representing all rows in the quality_control_reset table where there is
only one row for the most recent quality_control_range.  Help?

Example:

In table quality_control_reset, there are the following rows:

id   |   timestamp   |   qualitycontrolrange
---------------------------------------------
1    |  02/23/2006   |   20
2    |  02/23/2006   |   6
3    |  02/28/2006   |   18
4    |  03/01/2006   |   18
5    |  03/23/2006   |   12
6    |  03/23/2006   |   20

I want the results of the following from the query:

id   |   timestamp   |   qualitycontrolrange
---------------------------------------------
2    |  02/23/2006   |   6
4    |  03/01/2006   |   18
5    |  03/23/2006   |   12
6    |  03/23/2006   |   20



QualityControlReset.java:

package test;

import java.util.Date;

/**
  * @hibernate.class table="quality_control_reset"
  */
public class QualityControlReset {
    private Date date;
    private QualityControlRange qualityControlRange;

    public QualityControlReset() {
       // noop
    }

    /**
     * @hibernate.id generator-class="native" column="id"
     */
    public Long getId() {
       return id;
    }

    public void setId(Long long1) {
       id = long1;
    }

    /**
     * @hibernate.property not-null="true"
     */
    public Date getDate() {
       return date;
    }

    public void setDate(Date date) {
       this.date = date;
    }

    /**
     * @hibernate.many-to-one class="test.QualityControlRange"
cascade="none" not-null="true"
     */
    public QualityControlRange getQualityControlRange() {
       return qualityControlRange;
    }

    public void setQualityControlRange(QualityControlRange
qualityControlRange) {
       this.qualityControlRange = qualityControlRange;
    }
}


QualityControlRange.java:

package test;

/**
  * @hibernate.class table="quality_control_range"
  */
public class QualityControlRange {
    private String code;

    public QualityControlRange() {
    }

    /**
     * @hibernate.id generator-class="native" column="id"
     */
    public Long getId() {
       return id;
    }

    public void setId(Long long1) {
       id = long1;
    }

    /**
     * @hibernate.property
     */
    public String getCode() {
       return code;
    }

    public void setCode(String code) {
       this.code = code;
    }
}