How do you restrict employee from enrolling into an option?

Summary:

We have a requirement to suspend optional life insurance for elected coverage over $500K (GI), with interim coverage being $500K (GI).

Our first solution was to add an option called $500,000 Coverage and hide this option during enrollment. We hid this option using the Enrollment Rule of Current - can keep or choose; new - nothing. This worked as expected for the enrollment page however the $500,000 coverage option would not populate as interim coverage. It seems like when you restrict an option during enrollment, it restricts the option for interim coverage.

Our solution to work around the restriction issue was to remove the Enrollment Rule, allowing the employee to see the option but adding a Post Election formula, restricting the employee from electing the option. This works as expected if Pending Action (EOI) is approved, the elected coverage is then unsuspended and interim coverage ($500,000 Coverage) is removed. The issue is when Pending Action (EOI) is denied and the interim coverage now becomes the elected coverage, which is the $500,000 Coverage option. We receive the post-election formula error we received during enrollment, stating you can't elect this option.