Sync Quantity of Two Products in Cart

Site URL: https://www.sultan-travels.com/umrah-february-2025-package

I would like to have a product that has an add-on item sync quantities in the cart.

For example, I have a service that is $1500. I have an add-on product for "Card Processing Fee" for the item. However, if they were to add multiple quantities of the product (say 4), it would only have 1 add-on associated with it..    I would like the add-on product of "Card Processing Fee" to sync and also have 4 listed in the cart.