Deadline for creating an absence - Vacation plan

/We need to set up an error for the type of vacation absences that is generated in employee self-service when an absence is created after a certain date.

This date is different for each month of the year.

We thought of a quick formula. Does anyone know a way to do this?

Example:

Vacation absence :

Start Date 10/sept/2023

End date 15/sept/2023

The employee will create the absence on September 23, 2023 and the cut-off date is September 21, 2023. For this reason, an error must be generated and NOT ALLOW THE CREATION OF THE ABSENCE