As a workaround, you can make use of Address Group. To do that, you may follow these steps:

1. Go to Administration > Policy Objects > Address Groups.
2. Click Add.
3. Fill up the following:
   1. Name: Enter the Address Group name
      Toggle OFF Internal Group as it does not support wildcard domains
   2. Email Address: Enter the wildcard domain.
      Example: *@*.test.com.
4. Click Add then Submit.
5. Under your target policy exceptions, you may do the following:
   1. Go to Recipient and Senders.
   2. Select Specify then select My address groups.
   3. Add the address group you created.
   4. Click Submit.