Structured menu with groups

Hi guys,
I need your advice.
I am solving a problem with web structures for a hospital and its clinic.

The content of one clinic must be displayed on the same page.

My idea is to create a content structure with 2 levels.
The first level is the Clinic - display on site only slug
The second level is all other content - display on site with fullslug

But I don’t know how to resolve the header names of groups in the menu.
I need to edit the group headers and each clinic can have different groups.
Editing all of this must be user-friendly in administration.
Have any ideas?

A lot of thanks for your advice.

The menu scheme is as follows (menu in picture):

Does each clinic has his own subdomain or his own domain ? how will it work ? each clinic can have multiple locale ?

One domain = whole site. No subdomain, only content changing. Maybe later multi language content.