1

Is there a way like other recorders to set what contacts not to record?

2

The feature has already been there.

You can set Boldbeast Recorder to "auto record the call only when the telephone number is in a predefined list", or "auto record the call only when the telephone number is NOT in a predefined list".

Click the "Call Settings - Auto Record Calls - Rule to Auto Record Calls" option to set the rules.