Variable in a UNC path with a policy that finds a "Local" server

If I have multiple sites and servers, each with its own shares, Home dirs, My Doc redirect dirs, etc., how could I create a policy that would know to use the local server in a UNC path? In other words, create a policy that uses a variable (or something) to define which server it uses as its install point or home folder path.
for example: \\%Local_server_in_my_site%\software
or \\%server_in_my_site%\home\%username%

Where could I define (or lookup in AD) a local server (%server_in_my_site%) that is in my LAN (an thous has a fast connection)?

Now obviously I could use multiple different policies to accomplish the same thing this but I am looking to do this the fancy way.