Créate a "child hierarchy" of the default "Issue" hierarchy


I want to create a new hierarchy in the Issue dimension, which would be a child hierarchy of the default “Issue” hierarchy.
This hierarchy would be called “Child Tickets”, it would concern all my “Work” type tickets (and only these tickets). All my “Work” tickets have a “Parent ticket” link with an issue, which can be US, TS or anomaly. Each “Work” ticket has only one “Parent ticket” link.

Is it possible ? I’ve read these two articles and feel like I can only create hierarchies that are above the default “Issue” hierarchy

thanks in advance