Sometimes you have many jobs for different project groups, but showing group A
that group B works on xyz and they can see the minimal information (all matrix
authorizations revoked except read which they need globally to see their jobs)
is no solution neither setting up a hudson-server for every project group,
because the QA needs to see all jobs and don't want to login into dozens of
hudson-servers.

So my request is to add a feature which allows the administrator to define who
can see which jobs.

I would suggest the following configuration:
1. In the AccessControl option for admins add the option "Job: See all" in the
project based matrix (this would be for the QA, admins etc)
2. In the project based matrix of the job configuration add the option "Job: see"

With this two options it would be easy to manage which jobs each contributor can
see and would avoid setting up a hudson-server for every project group only to
prevent information lacks (that they can know of projects they should not ever
heard about it)