Get user role in time entry rule formula

We have business requirement that, we have 2 different types of Time Keepers

Section Time Keepers - Many users

Division Time Keepers - very few users.. kind of Division Administrators

Section Time Keepers will update employee timecards day-to-day & ensure attendance is up to date. Weekly timecards will be submitted automatically on the following Tuesday. Managers will approve in next 2 days.

Requirement is that, Section Time Keepers should NOT be able to do any more entries once manager APPROVES the timecards.

Only Division Time Keepers can do any further adjustments, if required.

To achieve this, I want to write a Time Entry Rule to check if Timecard is APPROVED & user who is entering more entries is Section Time Keeper, it will ERROR.