To create a group for all users that accept email please follow the steps below. 
  1. Create a query - Steps to create a query
  2. Go to the Query Builder tab.
  3. Select Email from the Field Type drop-down.
  4. Select Accepts Email for the Field drop-down.
  5. Select the Add Field Clause button.
  6. Select equals in the first drop down and True in the second drop down.
  7. Click the Save button.
  8. Click the Save Query button.
  9. Click the Run Query link.