Well, if it is not cofigured to emulate loop start trunks, it "hunting" could simply be sending DNIS to the next available channel.
You could have make the entire system work with a Merlin Magix, a T1 card, and a Merlin Messaging. Use DNIS to indicate the number dialed, instead of sending it to a particular channel, and the Magix would route the call to the appropiate mailbox. You could have 12 calls at a time to the same number (only because 12 ports is the maximum for Merlin Messaging - other voice mails could have a larger number of ports). 0-out to an external number can be handled with a phantom extension remote call forwarded to the outside number.
Any number of "real" phone systems could handle what you've cobbled together, and still don't have working yet.
