Google Voice now allows you to set rules for how the service responds to specific contacts. Yes, Google Voice can automatically ignore certain contacts for you.
With the new rules, you can set up a rule that forwards calls from a contact (or a group of contacts) to any of your linked numbers.
You can also create a rule that sends certain callers to voicemail if you don’t want them forwarded. Using this option, you can also customize voicemail greetings and block calls from specific contacts.
A rule can be created at voice.google (Note that the Google Voice mobile apps can only view rules, not create or manage them.) On the browser-based site, click “Settings” in the top right (represented by a cog icon). Click “Calls” and then “Create a rule.”
You can then choose which contacts to add a rule to, whether to screen the call, send it to voicemail, set a custom voicemail greeting, or forward it to a particular number. Visit Google’s support page for full instructions on how to set up each rule.