I send lots of mails to companies and mostly for the ones outside of the country. We work in a ticket base which is indicated in subject of the mail and they send e-mails from specific accounts.

The problem is that I sometimes can miss the conversations and think that I am waiting the response from these mails but normally they are waiting answer from me. This is because the tickets I opened are very much.

In short, I need to manage the tickets and understand that who respond last easily as not searching and finding the ticket number in Outlook.

To understand who responded last, I am marking the last conversation as Unread (in both sent and inbox sections).

1- Can there be a mechanism to unread an e-mail as putting a kind of check mark somewhere as replying the e-mail so after sending it, it will become unread in Sent items?
2- If the message responded from the customers to that unread mail, can this unread mail (in sent items) become read again automatically? It can be after after a period of time as well.