How to save private chats between participants

Hello, I am planning to do research on intrateam communication.

I will get consent from participants and then record the meeting.

I also want to get data of public chat and private chat.

Is it possible to save private chats between members? 

Also, should I always be in a meeting room to record the meeting or can I set the meeting to be automatically recorded? and the chat to be automatically saved? 

Please let me know. Thank you!