Visibility issue

[Daniel <danielnorberto@gmail.com>]

Hello,
I want to use a tagged type as a link to communicate users of a library, in the way to make one part visible to them and also to hide some content that is only needed for the implementing of the library.

Lets say i have the "Library" packages to expose things to users, and Implementing_Library packages to deal with the implementation:

package Library.Users is
   type User_type is tagged with private;
   procedure foo_public (S: User_Type);
private
   type User_Type is tagged with record
      hide_content_to_user : Natural;
   end record;
function Access_to_hide_content return User_type;
end Library.Users;

private with Library.Users;
package Internal_Library_Implementing is
-- Some internal public developer stuff
private
--Here I want to get access to User_Type hide content.
end Internal_Library_Implementing;

I've tried using "private with" but gnat says the next:
   move subprogram to the visible part (RM 3.9.3(10))
   private function with tagged result must override visible-part function

Compiler says Im forced to make all private User_type functions public.
So,  are there more ways to see the hided content of this tagged type without extending the type itself in a child package? I needed to see this content outside of Library package.