Using signal for group messages

[Bykiev]

Hi, I need to send one-way encrypted messages to user groups (admin sends messages into group). Does Signal protocol suits well for such task? I did some research and didn't find much docs about it. If I understand correctly, Signal encrypts and sends message for each user in a group which is not the best option for me. Do you have any demo, showing how to implement such group chat with your library?