If you want to allow long distance calls with an access code, you just have to put the Route Pattern in a partition, and create a Calling Search Space including this partition for users who are allowed to do this call.
For example, you want to allow calls to France for user A. You configure a Route Pattern for this type of call, 00033!, and you put this pattern in the partition France that you just created. Now you create a CSS which include the partition France and you assigne this CSS to user A. Now user A can call France.