This kind of interview is conducted by an interviewing panel that is made up of the supervisor and some members of the team. The interview panel can also consist of top level CEOs although this depends the kind of position you are applying for.
The panel interview is a way for the organisation to judge the communication level, interaction with a group and to assess the skill level of the candidate. You will be asked questions from all the panel members, sometimes the same question by different panel members. It is difficult to build the kind of connection with the interview panel as you can in a one on one interview.
You can buy time by asking questions. You should always remain calm and composed during a panel interview. Take a breath and even count to five (in your head), if you see the situation getting out of hand.