How to organize messages without losing information that may need to be referenced at a later time.

How do we archive old messages? We would like to be able to organize messages into groups such as a guest inquiring about a purchase one week and then a month later inquiring about service. We are able to use Tags but the information is bundled together. At times, guests message the team and it will be directed to the last assigned user. If this program could go automatically to an unassigned status after 24 hours, it would assist the admins to assign to the appropriate person again.