Mapping NetSuite Custom Fields with Snap Pack (SOAP)

I’m working on an integration here in which i get a list of customers from NetSuite. The customer info includes 4 custom fields. The custom fields comes in an array of objects and, if there of the fields are blank, its object wont come inside the array.

The question is, what is the recommend practice to work in this scenario. Is it safe to add loops inside the mapping snaps? W