Before I can offer practical suggestions, I need to know:-

Are you selling the dresses and bloomers TOGETHER as a single product (using ONE product code and ID), or is each a SEPARATE product?

If sold as ONE product, how do you allow the customer to buy one component without having to buy the other?

You could set up two option NAMES:-

1. Inscriptions for Dresses

2. Inscriptions for Bloomers

Then, under each of these option NAMES, you can set the option VALUES.

(Option Name) Inscriptions for Dresses
(Option value) Name, Single Letter, or Monogram (f, L, m)

(Option Name) Inscriptions for Bloomers
(Option value) Name, Single Letter, or Monogram (f, L, m)