How to set up eligibility based on SAL

Does anyone know how I would set up an enrollment eligibility based on an employee's salary?  We are trying to figure out if we can make E1 do an automatic enrollment into our Long-Term Disability Buy-up plan when processing batch enrollment for anyone who's salary has met the $30,000 requirement.  We are currently depending on timely communication for this notification and we only have a 30 day window to get an employee enrolled.