Add a filter for the whole view that checks username in both fields as not null, and set the operator to 'And'.
In your view under 'Filter Criteria' do the following:
- Add user name with the first relationship and set the operator to 'is not empty (NULL).
- Do the same for the second username field.
- Click the dropdown arrow next to add for 'Filter Criteria'. Select And/OR, Rearrange and add an 'AND' operator between the two filter.
- Hide the second username from display.
That way you can filter for users with both flags.