Group provisioning is not restricted by any licensing, merely the ability to assign groups to an application. You can still provision groups by using the "Sync all users and groups" provisioning option - typically accompanied by the scoping filters feature to take the initial set (ALL users/groups) and reduce it based on attribute values.
The actual goal you're looking for is not possible at this time, nor am I aware of it being on any feature roadmap. Azure AD has limited to no support for nested groups when it comes to Enterprise Apps, and there is no already defined concept of a "parent group" attribute in Azure AD, which means there is no attribute for Azure AD Provisioning to read and convey to ServiceNow.