Access a viewmodel method from a custom viewcell

Hi Guys i'm trying to implement and learn MVVM the best I can,

I'm tripping over on how to do this,

I have a listview which is bound to a List contained in my pages view model of the type:

public class DeliverySet : List<Box>
{
    public string OrderID { get; set; }
    public Address address { get; set; }
}

The grouping header template is bound to a custom viewcell which displays the OrderID and has a button for Deletion.

The pages view model contains a method for deleting an item from the list, database and a web service, how can I somehow execute this method from the view cell as the binding context is the DeliverySet type and I have no access to the parent pages view model?

Thanks!
Dave