My design need friends

[Namespace]

Hello. I hope one of you has a good idea to solve my design 
problem.
I have 3 files in two different sub packages.

Package Bar has the interface Drawable:
----
module Bar.Drawable;

interface Drawable {
protected:
	void _render();

package:
	final void render() {
		this._render();
	}
}
----

and, for example, the class Graphic:
----
module Bar.Graphic;

import std.stdio;

import Bar.Drawable;

class Graphic : Drawable {
protected:
	override void _render() const {
		writeln("Graphics.render");
	}
}
----

Package Foo has the class Window:
----
module Foo.Window;

import std.stdio;

import Bar.Drawable;

class Window {
public:
	void draw(Drawable d) {
		writeln("Window.draw");

		d.render(); /// Error: interface Bar.Drawable.Drawable member 
render is not accessible

	}
}
----

As you can see, I try to access the render method from drawable. 
But since Drawable is in another sub package, I have no access.
That is a situation where I liked to have 'friends' like in C++.

I have two solutions:
  1. Move Window from package Foo to the package Bar. But that's a 
ugly solution and I don't want to have any Window components in 
my Bar package.
  2. Make 'render' public instead package. That is my current 
workaround. But I don't like it much since each other could also 
access 'render', not only Window.

My question is: is there any other possible solutions? Any D 
magic?

Thanks in advance.