How do you create users and how do u create shared folders in cyrus?
What you have to do, is:
Create the shared mailbox. I will called it 'together' here
cyradm --user oxadmin <servername>
Now, give the right users the right rights for this new mailbox:
The lrswipcd part can change, it will depend on the rights you want to give the users. Use a specific username instead of anyone if you want to give only a few users certain rights.
sam together anyone lrswipcd
Now you can subscribe to it, at least in OX and Thunderbird, but I presume in every IMAP client.