You can put two copies of the same field on the same layout. Maybe a BeginDate field.
You can set one copy to display Tuesday, November 28, 2013 and the second displays 11/28/13.
They are displaying the same data in the same field in the same record. Edit one, the other changes.
They can not display different data, just in different formats.
perhaps you should use a portal to a related table.
Then your drop downs in related info can use fields in the portal's table or a table related to the portal's table. This way, you can use several related records and be able to select different data in each. This is how you fill in a line items portal on an Invoicing layout such as is found in the starter solutions that come with FileMaker 11 and 12.