Creating a Nested Translation

[ignatius-n]

Hello,
I'm wondering how can I create a nested translation such as
"admin.cruds.users.fields.firstName"

trying to create it as

group => 'admin.cruds.users.fields' 
key => 'firstName'
value => 'John'
// OR
group => 'admin.cruds.users.fields.'
key => 'firstName'
value => 'John'

doesn't return a translation but something like:

group => 'admin'
key => 'firstName'
value => 'John'

works just fine