How to prevent the saving of Irre records in custom extension TCA using a hook (in Typo3)?

Question

I am using a custom extension in typo3 version 9.5.8. It's TCA consists of some input fields and an irre. If the user deletes one of this Irre record and clicked the "save" button, I process the data by using a hook (processDatamap_postProcessFieldArray). I take this data and verify it against some conditions. If the conditions are not satisfied, the data must not be saved. In the case of Irre records, I am able to take it and check whether it is satisfying my conditions. But I am not able to prevent the saving/updating of the irre record to the database table. How can I do it ?

I tried using exit(),but it displays a white screen when the "save" button is clicked.

class ClassName
{
    public function processDatamap_postProcessFieldArray($recordStatus, $table, $recordId, $commandValue, DataHandler &$dataHandler)
    {

    }
}