group policy for laptop users

Here’s my dilemma:
If I connect to work via Cisco VPN client from a personal machine, everythings great. If I connect via a work laptop (joined to Win2k3 domain), performance is horribly slow. I imagine it is because I have My Documents/Application Data/Desktop redirected to a network share at work via group policy. What I am trying to figure out is how to set it up so the users redirection policies are denied, but only on certain machines (laptops). Any ideas?