as we know Windows media player allows only one window a time. I just recognized that it is possible to open VLC-player more than once, so one can probably watch more than one webcam a time. If you have windows media player as well, you may watch three cams a time or even more, may be VLC-player allows even more than two open windows.
VLC-player is freeware, you may find it via Google, it's easy to load. Only a bit difficult to add the wanted URL. I use the menue media (1. one in the row) and than the network (ctrl N) and paste the webcam-adress there. There might be better ways to ad the adresses and even keep them, but I didn't find out yet.
Good watching, Leonia