We have 100 users and we need 25 of those users to have Internet access and restrict Internet access for the remaining 75 users. Do you have a solution for this?

You can allow Internet access by creating packet filter rules for the 25 users. If you do not have any packet filter rules for the 75 users, they will not have Internet access, you do not need to create packet filter rules to restrict access for those 75 users.