The matrix is 9x9. No.1 can hear No.3, No.6 and No.7. No.2 can hear No.4, No.6 and No.7. No.4 can hear No.6. No.5 can hear No.7. We built the matrix by using 「confbridge」and 「originate」, but this method created much noise. On the other hand, this method is very complex, I think, it's not the bast solution. Please, give me some suggests or ideas. Thanks!!!