Select appropriate network printer for Remote Desktop based on Thin Client location

I'm setting up my organization's first Terminal Server / Remote Desktop Session Host (RDSH) for Lab use. We are a college, and I am wanting to use this server (or more servers configured similarly in a farm) to power other labs on campus as well. Each of those labs will have its own shared printer.

Ideally, the thin clients would not need to have any knowledge of the printer that is in the area, as they won't be needing to print in the first place. Because the thin clients are re purposed hardware, we will be installing windows 7 on them, joining them to the domain, and using Group Policy to lock them down to minimal thin clients.

Is there some way that I can use Group Policy or Logon Scripts to have the thin client's location (Organizational Unit or something) determine which printer installed on the Server should be allowed/default to a user connecting from a given thin client?

A friend of mine in a similar situation (but unable to add the thin clients to active directory) was only able to accomplish this by having different terminal servers. In the case that we couldn't join the thin clients to the domain, is there any way that we can determine access / default printer appropriately?

Do you have separate subnets for each of these labs? I would probably set up different profiles to be used depending on the different labs and dole the values out via DHCP. I've done similar at my employer except that it's separated by floors. Each floor has its own subnet, which is setup to a scope in DHCP. DHCP option 162 differs for each scope.