CM provides in depth control over you voice calls. One of the features is that you can either blacklist (block) or whitelist (exclusively allow) certain call destinations.
You can blacklist destinations per prefix, or based on a certain price/minute threshold. Routing restrictions can be specified per individual SIP Trunk.
Blacklisting per prefix:
Blacklisting on cost threshold:
Whitelisting per prefix:
By clicking on an existing blacklisted destination, prefixes can be added or removed: