I'd need to re-look at our location awareness triggers. If you can specify something that a scheduled job (using 'at' maybe) could set, you could use that to create a policy, assign it to a location. When a reg value is 1, policy A is used. When reg value is 2, policy B is used. Using 'at' scheduling, you could set the reg value based on the time.
Disclaimer: Not sure our location awareness supports reg values or any other external item that could be set ... The suggestion clearly only works if we have that feature :-)