public class JobAssignments
    {
        public JobAssignments()
        {
            m_people.Add("John");
            m_people.Add("Bill");
            m_people.Add("Frank");
            m_people.Add("Steve");

            m_jobs.Add("Architect");
            m_jobs.Add("Teacher");
            m_jobs.Add("Carpenter");
            m_jobs.Add("Plumber");

        }

        private List<string> m_people = new List<string>();
        public List<string> People { get { return m_people; } set { m_people = value; } }

        private List<string> m_jobs = new List<string>();
        public List<string> Jobs { get { return m_jobs; } set { m_jobs = value; } }
    };

<ListBox x:Name="listBox"
             Grid.Row="0"
             HorizontalContentAlignment="Stretch"
             DataContext="{Binding}"
             ItemsSource="{Binding People}"
             ItemTemplate="{StaticResource JobAssignmentDataTemplate}">
    </ListBox>

<DataTemplate x:Key="JobAssignmentDataTemplate">
            <Grid>
                <Grid.ColumnDefinitions>
                    <ColumnDefinition/>
                    <ColumnDefinition/>
                </Grid.ColumnDefinitions>
                <TextBlock Grid.Column="0"
                           Text="{Binding}"/>
                <ComboBox Grid.Column="2"
                          SelectedIndex="0"
                          ItemsSource="{Binding Jobs ???? }"/>
            </Grid>
        </DataTemplate>

ItemsSource="{Binding ElementName=listBox, Path=DataContext.Jobs }"/>

ItemsSource="{Binding RelativeSource={RelativeSource Self}, Path=Parent.Jobs}"/>

ItemsSource="{Binding ElementName= listBox, Path=Jobs}"/>

ItemsSource="{Binding Source={x:Static JobAssignments}, Path=Jobs}"

public class Person
{
  public string Name;
  public IEnumerable<string> Jobs;
}

public class JobAssignments
{
  public JobAssignments()
  {
    Jobs.Add("Architect");
    ...

    People.Add(new Person() { Name = "Bob", Jobs = Jobs });
    ...
  }

  private List<Person> m_people = new List<Person>();
  public List<Person> People { get { return m_people; } }

  private List<string> m_jobs = new List<string>();
  public List<string> Jobs { get { return m_jobs; } }
}