@scottvoth –
Hi, Scott!
After rethinking a little my own question, I consider that the first three behaviours that you described are too radical, but this was what I wanted. But you got me right! I want a special group just as a way to register members (automatically, at user registration) to the group blog. This can be easily achieved with the current CBOX options (and with a not complicated function), so my problem is solved, at least for now.
Thanks a lot for the intention to help me! I apologize for the inconvenience!
Best regards,
Iurie