Account plan: "Allow to rename sub-server domains within main domain"?

Hello!

I'd like to configure an account plan so that the server owner has the right to create sub-servers whose domains are sub-domains of his main domain.

He should also be able to later rename those sub-server domains, but - obviously - also only to sub-domains of his main domain.

He should not be able to rename his main domain.

Can that be accomplished? It would seem that the "Can rename domains" right applies to both his main domain and sub-domains, and if allowed, does not restrict what the target name is, even when I have "Allow sub-servers not under this domain" set to "No".