Can we create a dependent flexfield based on Absence start date duration

Summary

In the Create Absence Page, We want to have an additional flex field to show when employee chooses duration as Half Day with the flexfield values to be AM or PM (Morning or Afternoon).

Content

We have a requirement as below

We have an absence type with UOM as 'Days'

Employee linked to an Elapsed Work Schedule

When they record an Absence the Start Date and End Date have a Duration field against it to show whether this date is a Half Day or Full Day

We want to have an additional flex field to show when employee chooses duration as Half Day with the flexfield values to be  AM or PM (Morning or Afternoon).