Thank you for your post.
Since you won't have 66 instances (00 through 65) of "numviewed" in the current table, this number will appear in a second table with some key field linking the two tables together.
How do you know when the record is being viewed? Would this be done with an OnLayoutLoad? If so, then the script would increment that value in the second table.
In another layout, you could have a portal into the second table, and then filter the portal by the checkbox values less than 2.
Let me know what you have tried, what results you are expecting, and what are your actual results. This will help narrow the focus.