What is the best practice when an employee is multi employed across two PAYEs

Hi

Carole Weeks has an employee who joined their company in March 2022 and then joined a separate LTD/ PAYE on the same portal in November 2022. Carole cannot add the second employment to the system but cannot do so unless she is to leave out the NI number.

Please advise Carole on how the employee can be on both PAYEs to ensure the employee's tax is correct?

Thank you