Fetching EOs in Vertical Inheritance

Hi Everyone,

I am trying to use Vertical Inheritance,

Abstract ParentEntity "Applicant"

"Person" and "Company" as two Child entities of Applicant,

Person and Company both can have "Applications", so Applicant has
"toApplications" a toManyRelationship with "Application" table,

Applicant has a boolean field isActive,
Person has a field FirstName,

My goal is to fetch the applications where application.toApplicant isActive
= true and Person.FirstName = 'Saif' sorted by Person.FirstName.

Application does not have any direct relationship with Person.

What should be the Qualifier for such?

So far I could not find any :( What I did as workaround is to first fetch
all persons which are Active and typecast the Persons to NSArray<Applicant>
and us in qualifier with Applications like
Application.TO_APPLICATION.in(person), but I don't think it is a good way to
fetch, 

I will really appreciate any kind of suggestions,

Thanks,
Saif.