List Duplications

Basically, Right now, the list duplicates users… people_lb is the list…
when another user logs in, it adds everyone in the room twice, or something I want the list to not add duplicates. HOW?!!?!!?


////////////////////////////////////////////////////////// manage SOs
function manageSO() {
    // Create a remote shared object to keep track of the users.
    users_so = SharedObject.getRemote("users_so", user_nc.uri, false);

    users_so.onSync = function(userList) {
        trace("onsync fires");
        // keep hold of the current selection
        var curSelection = Application.people_lb.selectedItem.label;
        
        for (var i in users_so.data) {
            if (users_so.data* != null) {
                // populate the dp
                Application.people_lb.addItem({label:users_so.data*, data:users_so.data*}); //ADD USER TO THE LIST
            }
        }
        
        var hasMatch = 0;
        for(var j=0; j<Application.people_lb.length; j++){
            trace(">>> " + Application.people_lb.getItemAt(j).label);
            trace(">>> " + curSelection);
            if(Application.people_lb.getItemAt(j).label == curSelection){
                trace(">>> match");
                hasMatch = 1;
                Application.people_lb.selectedIndex = j;
                break;
            }
        }