The interview consisted of three parts:
1) group interview - a group of four interviewees had to discuss random topics (every interviewee had to prepare one topic beforehand - we've got an e-mail on the previous evening) and make arguments, while others (including 3 interviewers) had to question these arguments)
2) informal chat with 2 employees of the company - we were said that it didn't count for the result of the interview. We had an opportunity to ask questions about the company and any personal experiences of these employees
3) individual interview - 1 interviewee and 2 interviewers