Arrange the rules, most specific, at the top of the list. If an exact match isn't found, then it will move down the list until a more appropriate rule is found. (these are North American examples)
918005551212
91800
91866
91888
918
Toll free Directory Assistance would be picked up by the first rule.
Then the three toll free numbers could go out to one route but anything else that began with 918xxxxxxxxx, would be picked up by the third.
You can also specify which extension use which rules. So you could have a rule of "91" (12 digits) to cover long distance, and make it specific to all extensions but one, then have a rule "1" (11 digits) that is used by only one extension.
