You probably already know this, but just to be sure that those guys don't go looking in the wrong places: QlikView Administrators is a local group in the machine domain of the server where you installed the QlikView Management Service.
If you want to make life easier for them, you can suggest to create an AD Group with the exact same name, and add that group to the local group. From now on, all member management can be performed from within AD, instead of having to open a console session.
Can you actually confirm that using a domain group inside the QlikView Administrators actually work. I have a setup where this does not work. The management console shows that a given user is a member of my domain group and I have verified that the domain group is a member of the QV Admins group, but the management console does not show that the user has QV Admin rights.