We want to be able to leverage our existing wireless infrastructure to provide shoppers guest internet access.  Our locations use Cisco 3700i access points that are managed by a pair of 5520 controllers in our data center.  We'd like for the guest user to be able to access the guest ssid from the store's access point but rather than backhaul that traffic back through our DC we would rather guest internet traffic traverse out the internet circuit at the remote location rather than coming back over the MPLS circuit. We do not want to add additional access points at the remote locations. But we'd also like for the controllers to provide DHCP services for the guest users. While I am sure that this is doable is there a more preferred solution?  My only caveat is that I need to use our current access points and controllers