Groups are just a special class of component instance.
You may be confused by the group.entities method which is actually a wrapper (shortcut) for group.definition.entities.
As said, group definitions do not appear in the “In Model” component collection list (“Materials” inspector panel,) and group instances are automatically made unique if they aren’t, when manually entered for editing.
I know I’ve pointed you to this instructional thread in the past.
You really should use the bookmarking feature of the forum (or your browser.)
- Selecting Specific Entity, Group or Component (By Name)
(I explain in this thread how to access groups from the definition list.)
Also, you can ask the admins to unlock your previous topic if need be …