Groups of services assigned to group of users (ITIL aproach)

[judyckig]

My impression is CustomerID is designed to let one Customer to control ticket of his users.
But what do you think about such approach:

Imagine IT Company who has two main customers, each of them having 700+ users.
Each Customer has different set of services, so you can't use Default set of services while creating a new user, but you should check in your files what services were bought by the customer and attach those services one by one to the user.
Second situation is even worse:
One of the customers resigns from one service. OTRS admin has to detach the service from 700 users clicking them one by one during one day.

Is this a correct understanding of OTRS functionality?
Is there a special plugin to manage groups of users, assigning groups to Customers, creating user roles, attaching services and SLA to user roles or user groups? In my organisation there is also an informal difference to give higher SLA for VIP groups within one customer and one service.

I'd love to read more about handling such situations but so far I didn't find much about it in the documentation.

[yuri0001]

This feature available only by payed subscription (as add-on feature). See onhttp://www.otrs.org - subscription.