Hi Binu,

Can you have a look on user criteria which helps in restricting the access to catalogs

https://docs.servicenow.com/bundle/london-it-service-management/page/product/service-catalog-management/task/t_CreateAUserCriteriaRecord.html

Mark Correct if this solves your issue and also mark Helpful if you find my response worthy based on the impact.
Thanks
Ankur