cups access control

[maxmad]

Debian Linux Lenny

It seems to be a beginners problem, but I don't find the right combination in configuration.

It is a 192.168.136.XYZ network with three groups of computers:
group A: 192.168.136.10-20
group B: 192.168.136.30-40
group C: 192.168.136.50-60

and three printers
printer for A: 192.168.136.21
printer for B: 192.168.136.41
printer for C: 192.168.136.61

I would like to have printer A visible and printable only for group A and so on.

As soon as a printer is not published, it can't be accessed by anyone. Once published, everybody sees it and can print on it.
How can I make a printer visible and accessable only for one group?
Which parameters have to be set in printers.conf and cupsd.conf?
Thank you for helping.