You'll need to enter account codes in the Independant Accont Codes form.
Create a New COS that enables Forced account codes and assign it the restriced phones.
If you want them to be able to dial internally with out the account code, geive them a COR that does not allow outbound dialing (except for 911 of course) and give the account codes a COR that does. Then the user entered the feature code for the account code then then account code. At that point he will be able to dial out.
Ralph