Another object question

Ok I am trying to wrap my head around objects...

I have a base type that can display an object and handle input. When it is created, it goes into a master list for display items.

Now I extend that type do make the varrious display objects do different functions. One type of display object displays a player, another shows stats, etc. All of the functionality is handled here as to what happens when the player interacts with the object.

When I create I assume that I call the extended type to create both.

Now when I loop through the master display list, do I get the extended type as well as the base display type? Or do I need to have some kind of index to tie them together?

Example:

type displayitem
  method showitem()
    stuff...
  end method

  method new()
    displist.addlast self
  end method
end type

type playerselection extends basetype
  method handleinput()
    stuff
  end method

  method create()
    return new playerselection
  end method
end type

local p:playerselection
local a

for a = 1 to 1000
  p:playerselection = p.create()
next

Now when I loop through my display list do I do my eachin on playerselection objects, or displayobjects? If I do the loop on displayobjects (since that is what is added to the list) do I get the associated playerselection object as well?

I love this object stuff, but this is my first go with it. Neat and really functional!