Can I deactivate a static time definition?

We had a number of custom "static time definitions" used for calculating overtime across our multiple biweekly payroll definitions. We have since consolidated to one single definition, so most of these statis time definitions are now obsolete. There is no option to end date, and "delete" returns the error that it is assigned to employees. There are no active employees that still have this association, but terminated employees do.

Are there any options to deactivate these static time definitions? Or at least keep them from appearing in the "overtime calculation" dropdown box on the payroll relationship? We would like to prevent the obsolete definitions from being accidentally chosen in any new records.