[DefaultMemberAttribute("Item")] 
[SerializableAttribute()] 
public class GroupCollection : System.Collections.ObjectModel.Collection<Group> 

class MyPage : System.Web.UI.Page
{
   private List<string> GetGroupsBreadcrumb(string shopFilter, string[] items)
   {
       List<string> labels = new List<string>();
       GroupCollection gc = default(GroupCollection);
       string shopId = shopFilter;

       if (string.IsNullOrEmpty(shopFilter) || string.Compare(shopFilter, "ALL", true) == 0)
       {
           gc = Group.GetGroupsByIDs(items.Skip(3));
           shopId = items[2];
       }
       else
       {
           gc = Group.GetGroupsByIDs(items.Skip(2));
       }

       Dynamicweb.eCommerce.Shops.Shop sh = new Dynamicweb.eCommerce.Shops.Shop(shopId);
       labels.Add(sh.Name);

       foreach (Group g in gc)
       {
           labels.Add(g.Name);
       }

       return labels;
   }
}