What is the issue?
This is a description of how to create a content filter that will exclude an email from ALL but the front-line tests.
What is the solution?
Go to Content Filtering > Content Filtering and click Add....
Complete the fields in the Add Filter dialogue box as shown in this example, but replace firstname.lastname@example.org in the Value field with the email address you want to create the filter for. When using matches regular expression, you must escape any special characters by using a backslash (\) before the special character. For example, example\@domain\.com will bypass banned attachments sent from email@example.com:
For more information, see our Content Filtering and Using Regular Expression documentation.