Absence plan balance transfer during the changes in Bargaining unit

Summary:

We have two different Absence balance one is Annual leave and another one is annual leave RAC, we have differentiated with Bargaining unit, here if any employees department and Bargaining unit was updated then plan balance should be automatically transferred to another plan.
Please share a workaround ASAP.

Content (please ensure you mask any confidential information):

We are not facing any here, We are already having the Absence plan transfer rule like the Balance from Plan A will be automatically transferred to Plan B, but In our case If there is a change in Bargaining unit from A to C employee absence plan was changed from Plan A to Plan C then again balance will transfer to Plan C.