Give the users permissions.
i.e.
USERS
+------------------------
+ uid | uname | ulvl
+------------------------
1 | travis | 2
2 | demo | 1
3 | locked | 0
Users with a different ulvl get different access. You can require that a user have a ulvl of 1 or greater to view page A, while they must have a ulvl of 2 or greater for page B. A ulvl of 0 means deactive user.
With this method it takes a bit of planning, but it works.