DVD-A "Bonus Groups" protected by password!? (1 Viewer)

[Lewis Besze]

I have encountered this feature on 2 discs so far both from Rhino. Yes: Magnification,and ELP: Brain Salad Surgery.
On the ELP for instance Group 4 is labeled as "Bonus Group enter password".I've been an email correspondence with one of the member here who encountered the same issue on a different player[Denon,Pioneer],with same the massege on our screen.
Does anyone know what password these discs asks for and where to get it?
The manuall for my Denon mentions this briefly,but offers no clue for this password, the booklet for the affored mentioned titles,has no info either.

Any help is appreciated!

 

[Phil A]

I put my ELP disc in my Samsung HD1000 and hit the group button and it only showed groups 1,2 & 3. My Pioneer Elite DV-47A does not have a group button.