Marking message as read on two computers on the same accout

Hello, Me and my friend are sharing the same email accout, and we are both using EM-Client. Diffrent people are mailing to us and some of emails are important to him and some to me. When my friend marks as read emails directed to me on his computer, they are also mark as read on my computer after 5seconds. Does anyone knows how to avoid that?

If you are both configured to use the same eg: IMAP, Exchange or iCloud account, then if either one of you views an email, the other party will see the same email change to read status within a few seconds as is the nature of IMAP, Exchange & iCloud accounts. No way i know of to avoid that happening.