type TRec1 = record
  dertext : string;
  procedure ShowText;
end;

type TRec2 = record
  dertext : string;
  procedure ShowText;
end;

type TKlasse = class
  private
    FText : string;
    FDaten : TRec1;
    procedure SetText(Value : string);
  public
    property Text : string read FText write SetText;
    property Daten : TRec1 read FDaten;
end;

type TSubKlasse = class (TKlasse)
  private
    FDaten : TRec2;
  public
    property Daten : TRec2 read FDaten;
end;

//...

{ TRec1 }

procedure TRec1.ShowText;
begin
Showmessage('Rec1 '+dertext);
end;

{ TRec2 }

procedure TRec2.ShowText;
begin
Showmessage('Rec2 '+dertext);
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
test := TSubKlasse.Create;
test.Text := 'asdf';
test.Daten.ShowText;
test.Free;
end;

{ TKlasse }

procedure TKlasse.SetText(Value: string);
begin
FDaten.dertext := value;
FText := text;
end;