I am at a multi-site tuition centre. We have 2 email addresses (info@ and accounts@) which handle all issues for the company, from general sales enquiries, to scheduling issues, to accounting queries. These two email addresses are used across all sites. We currently have about 12 people reading every email coming into these addresses.

I am looking for an open source (or cloud hosted - as long as it is affordable) solution to lighten the load for our team. The solution needs to do the following:

1. Create tickets from emails. Allocate these to a queue based on email address, and potentially keywords.
2. Link tickets/emails from the same people (so we can track it) even if there is no "ticket no" in the subject line (we need to see communication history)
3. allocate all 10-15 "users" to queues. Some users will only use one group queue, while others will have their own queue, and probably multiple queues.
4. Replies in-system should be emailed to the original ticket creator.
5. People with access to a ticket (as it is in their queue), should be able to assign it to others.
6. an owner/manager of a queue should be able to see the progress of ticket items in any queue at any point.

Is there such a system?