Can it be done - Yes
Is it Simple - No.
You will need to be a sophisticated ARS programmer.
Create 2 routes for each of the types of calls you want to restrict.
One will be unrestricted by Cor Group
One Will be restricted by Cor Group
Create 2 route lists Each only having 1 of the routes above
Create a route Plan based on time of Day to use one list or the other.
In conjunction with this, I would enable verified account codes to override the restrictions for after hours use.
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Occam's Razor - All things being equal, the simplest solution is the right one.