You can to do this, to create a container, add all makers to container and zoom to map. for example:
var myContainer = new nokia.maps.map.Container();
$.each(data, function(i,val){
outletMarkers[val.id] = new Array();
var lat = parseFloat(val.latitude);
var lng = parseFloat(val.longitude);
outletMarkers[val.id] = new nokia.maps.map.StandardMarker(
[lat,lng],
{
text: val.text,
$click : 'showBubble("'+val.text+'",'+lat+','+lng+',false,"'+val.id+'");'
}
);
myContainer.objects.add(outletMarkers[val.id]);// add all makers to the container });
Add the container to the map map.objects.add(myContainer);
Zoom to all makers map.zoomTo(myContainer.getBoundingBox());