Our intercoms don't support black/whitelisting by default. However, you can do it in a PBX or using automation. If you'd like to use automation, you'll need Gold or Enhanced Integration license first.
The Number parameter under Event.CallStateChanged can contain a phone number of a SIP Proxy destination.
The following is an example of a whitelist. In case you'd like to make a blacklist, just swap Action.AnswerCall for Action.EndCall.
Please note that it's better to set up a whitelist, since blacklists can be easily bypassed by changing your number to a different one. For whitelisted values, you need to know the exact number that can get through.
Automation you can download here: Whitelist.am
There is an example how to configure it for more than one Number. Whitelist.am