Restrict incoming and internal calls to certain extensions

General Help
4

you could add new contexts for each group of extensions. for example if you had extension ranges 100-199 and 200-299.

[from-group-a]
exten => _2XX,1,Goto(app-blackhole,congestion,1)
exten => _[*0-9]!,1,Goto(from-internal,${EXTEN},1)
exten => h,1,Hangup()

[from-group-b]
exten => _1XX,1,Goto(app-blackhole,congestion,1)
exten => _[*0-9]!,1,Goto(from-internal,${EXTEN},1)
exten => h,1,Hangup()