Sure, you have three methods:
1 - COR list. you permanently block certain calls from certain phones
2 - PIN login & afterhours. Once logged with a per-phone pin in you can dial certain patters and also define a time schedule for this to happen.
3 - Custom steering digits. You create special prefixes to allow certain calls and this code is given to ppl kind of like an account number.
1 & 2 are explained in the sysadm guide and others CCO documents. 3 - is not but easy to figure out.
Hope this helps, please rate post if it does!
