mac mail view

I have account 1, account 2, account 3 and account 4 in my Mac mail. account 2 and account 4 are accessed by others too. I send an email from account 1 with account 5 with cc to account 2, account 3 and account 4. Now what's happening is that in my view for account 1, I'm able to view emails from account 2 and account 4. In setting, under viewing - include related messages are turned on. When I turn it off then I don't see the replied emails for the thread.

How can I achieve that I can see all communication for that subject and not for the other account?