I mentioned the flow in the original post as follows :
1. Caller calls a specific number on the switch.
2. Switch looks up callers caller id in database. If not listed, switch aborts the call with a Not In Service tone (or other tone that indicates the line is dead/inaccessible)
3. If listed in the database, switch then plays a dialtone or greeting, and allows caller to enter digits.
4. Digits are checked against a number plan, and if valid – call is routed to that number using the trunk assigned to that number plan.
The feature you have in place that comes close, requires a PIN as mentioned when I first requested this. The request is to have the option to use Caller ID and a lookup-table in place of a PIN on that feature.
