Allow new user to manage multiple clients

In the server documentation, it says “The more sophisticated rights editor can be used to allow an account to access several clients or to limit some aspects.”

So where do I access this editor? I tried to edit an existing user where it allows me to add new domains, but it seems that it does not allow me to assign rights to new clients for the same user.

Is it possible for the same user to have access to multiple clients at the same time?

Further on:

You can set the domains not marked with stars(*) either to one or several client ids (separated by ’,’)
or to ’all’ - meaning the account can access all clients.

It is not really nice as you somehow have to find out the clientid of the client and then enter them as a comma separated list.