Elastic search with retreving 1st element of array

hello all, my current problem with search criteria is as below
data:- person{
name...bunch of props
cards:[
amexcostco:[nbr:123456789
nbr:xxxxx89]
]
}

is there anyway i can search based on a criteria and just retrieve masked property every time unless specifically asked for?

i mean i should get all persons that match a property(match query) and retrieve all cards but each card result get nbr-attribute's 2nd property(plz note the nbr field's name is same for masked and unmasked values)

result: person:{props.... cards:[amexcostco:[nbr:xxxxxx],amexmacy:[nbr:xxxx]]