can mutateFormDataBeforeCreate save more than 1 record

Hi, I made a hotelReservationResouce that has repeater form. the use of repeater is to record a room reserve by guest. so when user fill the forms, with 2 room, the record will save 2 record. i usuallly use mutateFormDataBeforeCreate to save record, but when it comes in 2 record or more, it not working. Any idea how to doit ?