How can we add a new record in between already existing seniority date records in 25D

Currently when we want to add a new record of seniority date in between already existing seniority date , we have to alter all the records to the dates after so that they reflect the orginal date that existed for that employee ..

Inserting a new record of seniority date changes the already existing record dates , how can this be prevented and not have us update or correct all the dates after the new record has been added ?

This is very time consuming because sometimes one employee can have multiple records which involves updating all of them ..