Asterisk Conference Bridge (Blind Listening and ...)

Please read this scenario and give me suggestion how to fix it. It is really major for me

I work with Asterisk 12. There are 3 Users , caller,operator,admin

Scenario is;

  1. caller call to operator
  2. operator answer it and talk
  3. admin must have ability to listen their talk, but blindly (I means operator and user do not know about this).
  4. If there is a need for something admin must have ability to get involved their talk

I think I will use Conference Bridge, but I don’t know how to fix blind listening issue.

Are there any suggestion?

Chanspy + Mute doesn’t work for you?

Thank you man, for your advice, I will try it