Creo que lo más sencillo es hacer esto:
Código Delphi
[-]
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, Menus,
unit2, unit3;
type
TForm1 = class(TForm)
private
public
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
.........
.........
.........
Código Delphi
[-]
unit Unit3;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, Menus;
type
TForm3 = class(TForm)
private
public
end;
var
Form3: TForm3;
implementation
uses unit1;
{$R *.dfm}
.........
.........
.........
Saludos.