Extension restriction on future codes

Hi ,
I need to restrict some extensions from dialing future codes.
Any help of doing this ,the best way…Maybe by creating a custom context ?

Yes you can do it with a custom context, all those feature codes are defined in

[from-internal-additional] and the standard extension context [from-internal] includes that, add [my-from-internal] to /etc/asterisk/extensions_custom.conf and modify that to your liking , presumable without from-internal-additiona but adding those you want from that context, use my-from-internal as the extensions context (you can also do that from the GUI with good old “custom contexts” module).

Thank you dicko.
Working like a charm.
Will take in account the Class of Service Module for later purchase.