Monitor configurations

We would like to have 4-monitors on a Windows XP system,
three in a row on the operators table and one larger one on the
wall above.  The user interaction would be mainly with the three
on the table. The one on the wall above would be mainly for
display.   Is it possible to do this in such a way that the mouse
moves the cursor in a uniform way between the monitors?
Or do we need a separate computer for the wall monitor?
--JohnH