how to set rules in nnrp.access

[R. P. Joshi]

hello
i am using inn 2.2.2-3 in RedHat 6.2 box.
i am using nnrp.access to provide read and post permissions to a group of hosts

my question is :

HOW to provide a particular host or group of host (say  *.foo.com ) to
READ(only read) a perticular newsgroup and READ and POST (both) to other news
group.
that is :
all the hosts at foo.com should able to Read and Post in newsgroup2 but only a
READ permission for newsgroup1

How to set rule for this access in nnrp.access