Restricting Content Zone by Expense and Inventory Item to the user

Summary

Restricting Content Zone by Expense and Inventory Item to the user

Content

Here is my requirement

We have Expense item ( Destination EXPENSE) and Inventory Stock Item (Destination INVENTORY)

We want to create 2 content zone as follows

1. One content zone associated with local catalog will allow user to search both type of items
2. Another content zone associated with local catalog will allow user to search only Expense items

We are trying to restrict this while defining the Catalog by selecting the options Include Items from specific categories.

Our challenge now to assign this content zone to assign 1000+ users, is there a simple way or role based control can be achieved that a set of users can access each content zone based the content zone they have assigned? We really cannot assign to individual user, this will be too much maintenance.