CVS - access of modules per user

[Guntupalli santhi]

Hello,
   I am using CVS on Linux. I have a requirement.
I have different number of modules. each module corresponds to one directory. I 
want to restrict access ( checkin and checkout) of these modules based on user. 
Suppose like i have module "Test" and have user "tester1". The module Test 
should be accessable (  checkin and checkout)only to the user tester1. No other 
user should able to checkin or checkout this module. How to restrict users from 
using module. if i mention user name in reader and writers this will be global 
to all the modules. It will not help my requirement. Is there any other option 
for restricting users from modules being used. Any pointers are highly 
appreciated.

regards
- santhi