Dynamic time conditions for outgoing calls

Hello everybody,

Here is my problem in a nutshell:

Need to be able to enable/disable outgoing calls on an extension based on a per extension basis based on the time of day.

for example
extension 101
no external calls restricted:
mon from 9AM - 11AM & 2PM - 3PM
tue from 10AM - 12PM & 1pm - 2PM
wed from 9AM - 10AM, 11AM-12AM, 2pm-3PM
etc, all other times outgoing permitted
extension 102
no external calls restricted:
mon from 8AM - 9AM & 1PM - 4PM
tue from 10:30AM - 12PM & 1pm - 4PM
wed from 10AM - 12AM, 2pm-3PM
etc, all other times outgoing is permitted

internal calls and Emergeny numbers are permitted all the time

I have found the post Time conditions for outgoing calls http://www.freepbx.org/forum/freepbx/users/time-conditions-for-outgoing-calls, this seems like a start but from what I can see is a global setting not sure how I would go about changing this to extension centric…
and just to complicate things one step further potentially am looking at 50 sites each with anywhere from 10-50 extension per site which would have the restricted times having to change anywhere from 1-3 times a year depending on the instructors schedule for that semester

Any insight on the simplest way to accomplish this is appreicated