Yes, in the textures folder (what ever that window is called) type in "tools" and you will see a green texture that is called" block light. Simply put some brushes around the window to block the light.
BUT! that wont work because that means its blocking all the light and it would look really wierd.
SO!
what you can do is:
the brushes you just put around the window.. take those and skew them to a larger size so that its maybe twice the size of the window now... then place those brushes on the wall and have the light_spot inside right by the window... and if it works it should look exactly how you want it too.. just make sure there are no other lights in the hall that would make it look wierd.
AND! if that doesnt work.... experiment with other things.. maybe make the inner angle small and same with the outer angle...
Hope this helps.