strange behavior

I'm wondering if anyone else has had this problem. I'm admin for a list and all mail sent to the list address gets to me and no-one else, but all mail I send to the list goes to everyone on it. Any idea what the problem would be here? We are running a few other smartlists on our server and don't have this trouble (this is the only list that has digests). Help! Any leads appreciated! Drew Krause