There usually is only one external VGA outlet on your laptop (if it has one). Whatever gadget you hook up to this VGA port there will be only 1 set of display image no matter how many splitters you have.Quote from Bullverine:
I have the same problem I am attempting to connect two external monitors to my laptop. What I have done is obtained a VGA splitter that allows me to connect two external VGA devices to a single VGA port on my laptop. What has happened is exactly what I thought would happen (but hoped it would not), both external monitors are showing the same picture. My laptop screen is screen 1 and my first and second external monitors are screen 2 .
.....
If you want 3 different screen displays generated by your laptop, most likely your solution can only be those USB-VGA kind of device. (Or some uses PCMCIA I think). As discussed upthread.