The simplest would be to break up that single record into 5 related tables. Then you are searching only one field. This would likley be a better design for your database as well.
If you have FileMaker 11, you might be able to use quick find to search all the "Father" fields.
And a script could be used to generate the needed 5 requests with "Smith" specified in a different field on each request.
Thanks Phil. That might work. Thinking it through. Would you just put a button on the layout that would create a pop up dialog box so the user could input "Smith" and perform the quick find? Emmett
Yes, Show custom dialog can specify an input field for the search criteria and there's a script step you can use to perform a quick find and it can reference the data from the input field for the criteria used to perform it.