Restricted view of public folder.

Hi,

I need to give restricted access to the items in a public folder on an exchange server. For example, Lets assume that there is a public contact folder with 100 contacts in that. Now there are say 5 users who have access permissions to this public contact folder. What we need to implement is that all 5 users should not be able to see all 100 contacts. I want to define a criteria which says that a particular user can see only a certain number of contacts out of all the contacts present in this public contact folder.

Could somebody please let me know if such a thing is possible and if yes, then how to go ahead and achieve it.

Thanks
Vinay