Adding validation on list type roster that confirm the first entry is household name

how to add expression on list type roster to make sure that the first entry is household head

Imply the status ‘head’ for the first person and don’t ask that question for the first person.
Correspondingly don’t offer category head for any person, since for 1 it is automatically implied, and for the others - will always be invalid.

Hello, sergiy
How we can add validation condition that would trigger the first selected relationship is exactly head for the following single select question '4. What is %rostertitle%'s relationship to the head of household?(HEAD
SPOUSE
SON / DAUGHTER
GRANDCHILD
FATHER / MOTHER
SISTER / BROTHER
NIECE / NEPHEW
UNCLE / AUNT
SON / DAUGHTER IN LAW
FATHER / MOTHER IN LAW
SISTER / BROTHER IN LAW
GRANDPARENTS
OTHER RELATIVES
SERVANT
NON RELATIVES)

What is the point to offer options SPOUSE and below for the person listed in line 1?