Vista - Windows Calendar - Store ICS files on Network Drive and Share calendars?

I have 2 computers with Windows Vista and Windows Calendar. I want to store
my Calendar file on my Y Drive (which is my NAS device) and accessible by
BOTH computers. Both computers can STORE their .ICS files on the Y
drive...but when Computer 1 wants to SUBSCRIBE to Computer 2's ICS file on
the common Y:\ drive I get an error message "an error occurred during the
subscription process. The filename, directory name. or syntax is
incorrect." I am 100% sure the file name and directory are correct...it is
as if Windows Calendar is SPECIFICALLY looking for some sort of URL
(http://domain.com) to connect to though??

Is there ANYWAY that 2 computers on the SAME network can VIEW each other's
calendars without putting the calendar on some sort of Internet site?

Seems like such an easy thing to do.....but I am not sure if windows
calendar was meant to be used this way or not?

Thanks....

Chris Hagler