Here are some rules that we’ve helped customers create that might be useful to you as well
Rule: Import only selected email addresses
To set this up:
Create a new rule and give it a name
Set the Rule Type to Regex
Set the Rule field to this value: /^(?!(email1@domain1|email2@domain2|email3@domain3)$).*$/
Edit the value you entered into the Rule field to replace the email1@domain1 string to the email address you want to keep. You can replace email2@domain2 and email3@domain3 as well so you can keep up to three email addresses
Set the Where should this rule apply field to Sender’s email address
Check the Is Rule Action box.
Set the Action option to either Delete or Skip.
Click the Publish button.
This rule will ignore all emails except the email addresses you specified in step 4 above.